1. What is fabric and fabric management? Ans: A fabric is a virtual space in which all storage nodes communicate with each other over distances. It can be created with a single switch or a group of switches connected together. Each switch contains a unique domain identifier which is used in the address schema of the fabric. In order to identify the nodes in a fabric, 24-bit fibre channel addressing is used.Fabric services: When a device logs into a fabric, its information is maintained in a database. The common services found in a fabric are: Login Service: Name Service Fabric Controller Management Server Fabric Management : Monitoring and managing the switches is a daily activity for most SAN administrators. Activities include accessing the specific management software for monitoring purposes and zoning.2. What is ISL? Ans: Switches are connected to each other in a fabric using Inter-switch Links (ISL).3. Switch fabric ? Ans: Switched Fabric - Each device has a unique dedicated I/O path to the device it is communicating with. This is accomplished by implementing a fabric switch.4. Lun Migration? Ans: LUN Migration Information:LUN Migration provides the ability to migrate data from one LUN to another dynamically. The target LUN assumes the identity of the source LUN.The source LUN is unbound when migration process is complete. Host access to the LUN can continue during the migration process. The target LUN must be the same size or larger than the source.The source and target LUNs do not need to be the same RAID type or disk type (FCATA). Both LUNs and metaLUNs can be sources and targets.Individual components LUNs in a metaLUN cannot be migrated indepedently - the entire metaLUN must be migrated as a unit.

The migration process can be throttled. Reserved LUNs cannot be migrated.5. What is heterogeneous? Ans: A network that includes computers and other devices from different manufacturers. For example, local-area networks (LANs) that connect PCs with Apple Macintosh computers are heterogeneous.6. What is zoning? What all the different types of zoning? Ans: There are several configuration layers involved in granting nodes the ability to communicate with each other:Members - Nodes within the SAN which can be included in a zone.Zones - Contains a set of members that can access each other. A port or a node can be members of multiple zones.Zone Sets - A group of zones that can be activated or deactivated as a single entity in either a single unit or a multi-unit fabric. Only one zone set can be active at one time per fabric. Can also be referred to as a Zone Configuration.In general, zoning can be divided into three categories:WWN zoning - WWN zoning uses the unique identifiers of a node which have been recorded in the switches to either allow or block access A major advantage of WWN zoning is flexibility. The SAN can be re-cabled without having to reconfigure the zone information since the WWN is static to the port.Port zoning - Port zoning uses physical ports to define zones. Access to data is determined by what physical port a node is connected to. Although this method is quite secure, should recabling occur zoning configuration information must be updated.Mixed Zoning Mixed zoning combines the two methods above. Using mixed zoning allows a specific port to be tied to a node WWN. This is not a typical method.

7. what is Single HBA Zoning? Ans: Under single-HBA zoning, each HBA is configured with its own zone. The members of the zone consist of the HBA and one or more storage ports with the volumes that the HBA will use. Two reasons for Single HBA Zoning include:Cuts down on the reset time for any change made in the state of the fabric.Only the nodes within the same zone will be forced to log back into the fabric after a RSCN (Registered State Change Notification).8. What is LUN Masking? Ans: Device (LUN) Masking ensures that volume access to servers is controlled appropriately. This prevents unauthorized or accidental use in a distributed environment. A zone set can have multiple host HBAs and a common storage port. LUN Masking prevents multiple hosts from trying to access the same volume presented on the common storage port.9. What is iSNS (Internet Storage Name service)? Ans: Each Fibre Channel Name Service message has an equivalent iSNS message. This mapping is transparent, allowing iFCP fabrics with iSNS support to provide the same services that Fibre Channel fabrics can.When an iFCP or iSCSI gateway receives a Name Service ELS, it is directly converted to the equivalent iSNS Name Service message. The gateway intercepts the response and maps any addressing information obtained from queries to its internal address translation table before forwarding the Name Service ELS response to the original Fibre Channel requester. 10. What is Replication? Replication Software?Ans: Local replication is a technique for ensuring Business Continuity by making exact copies of data. With replication, data on the replica will be identical to the data on the original at the point-in-time that the replica was created. Replica - An exact copy (in all details) Replication - The process of reproducing data Examples:Copy a specific fileCopy all the data used by a database applicationCopy all the data in a UNIX Volume Group (including underlying logical volumes, file systems, etc.)Copy data on a storage array to a remote storage array

EMC Symmetrix Arrays EMC TimeFinder/Mirror Full volume mirroring EMC TimeFinder/Clone Full volume replication EMC TimeFinder/SNAP

Pointer based replicationEMC CLARiiON Arrays EMC SnapView Clone Full volume replication EMC SnapView Snapshot Pointer based replication

11. CLARiiON CX3-80 Architecture?Ans: The CLARiiON architecture includes fully redundant, hot swappable components meaning the system can survive the loss of a fan or a power supply, and the failed component can be replaced without powering down the system.The Standby Power Supplies (SPSs) will maintain power to the cache for long enough to allow its content to be copied to a dedicated disk area (called the vault) if a power failure should occur.Storage Processors communicate with each other over the CLARiiON Messaging Interface (CMI) channels. They transport commands, status information, and data for write cache mirroring between the Storage Processors. CMI is used for peer-to-peer communications in the SAN space and may be used for I/O expansion in the NAS space.The CX3-80 uses PCI-Express as the high-speed CMI path. PCI Express architecture delivers advance I/O technology delivering high bandwidth per pin, superior routing characteristics, and improved reliability.When more capacity is required, additional disk array enclosures containing disk modules can be easily added. Link Control Cards (LCC) connect shelves of disks.12. What is Control Station?Ans: A Control Station is a dedicated management, Intel processor based computer running EMC Linux to provide:Specialized software installation and upgrade portal Management of high availability features Fault monitoring Fault recovery Fault Reporting (CallHome) Management of Data Mover configuration and storage for the system configuration database Remote diagnosis and repair13. What is Fiber Channel?Ans: Fibre channel is a set of standards which define protocols for performing high speed serial data transfer. The standards define a layered model similar to the OSI model found in traditional networking technology. Fibre Channel provides a standard data transport frame into which multiple protocol types can be encapsulated. The addressing scheme used in Fibre Channel switched fabrics will support over 16 million devices in a single fabric.14. How To make LUN Available to host?Ans: Making LUNs available to a host is a 3-step process: 1. Create a RAID GroupChoose which physical disks should be used for the RAID Group and assign those disks to the group. Each physical disk may be part of one RAID Group only.2. Create LUNs on that RAID GroupLUNs may be created (Note: The CLARiiON term is bound) on that RAID Group. The first LUN that is bound will have a RAID Level selected by the user; all subsequent LUNs must be of the same RAID Level.

3. Create storage group and Assign those LUNs and host to storage groupWhen LUNs have been bound, they are assigned to hosts. Normal host procedures, such as partitioning, formatting and labeling, will then be performed to make the LUN usable. The CLARiiON software that controls host access (LUN Masking) to LUNs is Access logic.

15. How you will check compatibility for server when youre installing new box? Ans: Compatibility Matrix in E-Lab Interoperability navigator powerlink.emc.com16.What is Hot Spare?Ans: A hot spare is an idle component (often a drive) in a RAID array that becomes a temporary replacement for a failed component.For example:The hot spare takes the failed drives identity in the array.Data recovery takes place. How this happens is based on the RAID implementation:If parity was used, data will be rebuilt onto the hot spare from the parity and data on the surviving drives.If mirroring was used, data will be rebuilt using the data from the surviving mirrored drive. The failed drive is replaced with a new drive at some time later.One of the following occurs:The hot spare replaces the new drive permanentlymeaning that it is no longer a hot spare and a new hot spare must be configured on the system.When the new drive is added to the system, data from the hot spare is copied to the new drive. The hot spare returns to its idle state, ready to replace the next failed drive.Note: The hot spare drive needs to be large enough to accommodate the data from the failed drive

Hot spare replacement can be:Automatic - when a disks recoverable error rates exceed a predetermined threshold, the disk subsystem tries to copy data from the failing disk to a spare one. If this task completes before the damaged disk fails, the subsystem switches to the spare and marks the failing disk unusable. (If not it uses parity or the mirrored disk to recover the data, as appropriate).User initiated - the administrator tells the system when to do the rebuild. This gives the administrator control (e.g., rebuild overnight so as not to degrade system performance), however, the system is vulnerable to another failure because the hot spare is now unavailable. Some systems implement multiple hot spares to improve availability.16. What is Hot Swap?Ans: Like hot spares, hot swaps enable a system to recover quickly in the event of a failure. With a hot swap the user can replace the failed hardware (such as a controller) without having to shut down the system.17. Data Availability at the host? Ans: Multiple HBAs: Redundancy can be implemented using multiple HBAs. HBAs are the hosts connection to the storage subsystem.Multi-pathing software: Multi-pathing software is a server-resident, availability enhancing, software solution. It utilizes the available HBAs on the server to provide redundant communication paths between host and storage devices. It provides multiple path I/O capabilities and path failover, and may also provide automatic load balancing. This assures uninterrupted data transfers even in the event of a path failure.Clustering: Clustering uses redundant host systems connected together. In the event that one of the hosts in the cluster fails, its functions will be assumed by the surviving member(s). Cluster members can be configured to transparently take over each others workload, with minimal or no impact to the user.18. What is HBA?Ans: The host connects to storage devices using special hardware called a Host Bus Adapter (HBA). HBAs are generally implemented as either an add-on card or a chip on the motherboard of the host. The ports on the HBA are the hosts connection to the storage subsystem. There may be multiple HBAs in a host. The HBA has the processing capability to handle some storage commands, thereby reducing the burden on the host CPU.19. What Volume Manager?Ans: The Volume Manager is an optional intermediate layer between the filesystem and the physical disks. It can aggregate several smaller disks to form a larger virtual disk and make this virtual disk visible to higher level programs and applications. It optimizes access to storage and simplifies the management of storage resources.20. DAS,NAS,SAN?DAS : In a Direct Attached Storage (DAS) environment, servers connect directly to the disk array typically via a SCSI interface. The same connectivity port on the Disk array cannot be shared between multiple servers. Clients connect to the Servers through the Local Area Network The distance between the Server and the Disk array is governed by the SCSI limitations. With the advent of Storage Area Networks and Fibre Channel interface, this method of Disk array access is becoming less prevalent.NAS: In a Network Attached Storage (NAS) environment, NAS Devices access the disks in an array via direct connection or through external connectivity. The NAS heads are optimized for file serving. They are setup to export/share file systems. Servers called NAS clients access these file systems over the Local Area Network (LAN) to run applications. The clients connect to these servers also over the LAN.SAN: In a Storage Area Network (SAN) environment, servers access the disk array through adedicated network designated as SAN in the slide. SAN consists of Fibre Channel switches that provide connectivity between the servers and the disk array. In this model, multiple servers can access the same Fibre Channel port on the disk array. The distance between the server and the disk array can also be greater than that permitted in a direct attached SCSI environment. Clients communicate with the servers over the Local Area Network (LAN).21.What is DPE2?Ans: All CX-series models now ship with the new UltraPoint Disk Array Enclosure (DAE2P).

22.What is CRU signature?Ans: The CRU Signature defines what Enclosure/ Bus/ Slot the disk is in. It also has an entry that is unique for each RAID group so a disk not only must match the Bus/ Enclosure/Slot but also the RAID group in order to be included in as part of a LUN. If you pull one disk, that slot is marked for rebuild. If you pull a second disk from a RAID group, the RAID group shuts down. If you then insert a new disk for the second disk that you pulled, Flare (the array operating system) will try to bring up the LUN in "n -1 disks mode" but since it is not the original disk, it cannot bring the LUN online and, instead, returns a CRU signature error. If you insert the right disk (that is, the one you pulled from that slot), the LUN will come back online. If you were to insert a new disk into the first slot you pulled or insert the original disk that you pulled from that slot, the disk will be rebuilt because that first slot is marked as needing a rebuild. When a slot requires a rebuild, the CRU signature of the disk does not matter. A rebuilt disk is assigned a new CRU signature.The CRU Signature is created when a LUN is bound and is stored on the private area of each disk.23. What is CMI and Function?Ans: SPs communicate via the CMI or PCI Express bus CLARiiON Messaging Interface New models will use the faster PCI express bus A Fibre Channel connection between the SPs, called the CMI, carries data between the SPs, and also carries status information. On FC-series arrays, the CMI is a single connection, running at 100 MB/s. On CX-series arrays, the CMI is a dual connection, with each connection running at 200 MB/s. On newer CX3 series arrays, the communication path between SPs will use the faster PCI express busOn FC-series arrays, there is an internal mechanism to determine where the fault lies if the CMI should fail it uses a backup CMI, which is a low-speed serial connection between the SPs. On the CX arrays, the dual CMI itself allows this determination.

24. Explain raid levels? Ans: RAID 0 Striped Array with no Fault Tolerance RAID 1 Disk Mirroring RAID 1+0 Mirroring and Striping RAID 3 - Parallel access array with dedicated parity disk RAID 4- Striped array with independent disks and a dedicated parity disk RAID 5 - Striped array with independent disks and distributed parity RAID 6 - Striped array with independent disks and dual distributed parity

25. What is PSM LUN? Ans: A PSM LUN was created during installation or immediately after a CLARiiON FC4700 array was installed.The PSM LUN was not properly planned or the customer did not want the type of RAID Groups or LUNs that were configured. Destroying and recreating the PSM LUN assumes that no data has been stored on the array and that the procedure takes place during the initial installation of the array. While RAID Group and LUN information is unaffected, all Access Logix configuration information (including host mappings, storage groups, host information, etc.) and all configuration information for optional SnapView and MirrorView software are lost.26.How to create raid groups, binding Lun, create storage group?Ans: Right click Array properties create raid group, Right click Array properties bind Lun, Right click Array properties Storage group27. What is mirror view?Ans: MirrorView is the CLARiiON remote disaster recovery solution. Two arrays have dedicated connection over Fibre Channel or T3 lines. It is synchronous mirroring, meaning that all writes to the source must be completed to the Secondary array before the acknowledgement is sent to the source host. During a disaster, the Secondary Image can be promoted and mounted by a Standby host, minimizing downtime.28. What is Remote replication ? Ans: Remote Replication: Replica is available at a remote facility Could be a few miles away or half way around the world Backup and Vaulting are not considered remote replication Synchronous Replication Replica is identical to source at all times Zero RPO Asynchronous Replication Replica is behind the source by a finite margin Small RPO Connectivity Network infrastructure over which data is transported from source site to remote site 29. What is DWDM? Ans: Dense Wavelength Division Multiplexing (DWDM)DWDM is a technology that puts data from different sources together on an optical fiber with each signal carried on its own separate light wavelength (commonly referred to as a lambda or ).Up to 32 protected and 64 unprotected separate wavelengths of data can be multiplexed into a light stream transmitted on a single optical fiber.30. What all storage Arrays & SAN Devices supported by EMC ECC? Ans:Storage arrays:EMC SymmetrixEMC CLARiiON EMC CenteraEMC Celerra and Network Appliances NAS servers EMC InvistaHitachi Data Systems (including the HP and Sun resold versions) HP StorageworksIBM ESSSMI-S (Storage Management Initiative Specification) compliant arrays

SAN Devices:EMC Connectrix Brocade McDataCiscoInrange (CNT)IBM Blade Server (IBM-branded Brocade models only)Dell Blade Server (Dell-branded Brocade models only)

31. What is reserved pool?Ans: The CLARiiON storage system must be configured with a Reserved LUN Pool in order to use SnapView Snapshot features. The Reserved LUN Pool consists of 2 parts: LUNs for use by SPA and LUNs for use by SPB. Each of those parts is made up of one or more Reserved LUNs.The LUNs used are bound in the normal manner. However, they are not placed in storage groups and allocated to hosts, they are used internally by the storage system software. These are known as private LUNs because they cannot be used, or seen, by attached hosts. Like any LUN, a Reserved LUN will be owned by only one SP at any time and they may be trespassed if the need should arise (i.e., if an SP should fail). Just as each storage system model has a maximum number of LUNs it will support, each also has a maximum number of LUNs which may be added to the Reserved LUN Pool.The first step in SnapView configuration will usually be the assignment of LUNs to the Reserved LUN Pool. Only then will SnapView Sessions be allowed to start. Remember that as snapable LUNs are added to the storage system, the LUN Pool size will have to be reviewed. Changes may be made online.LUNs used in the Reserved LUN Pool are not host-visible, though they do count towards the maximum number of LUNs allowed on a storage system.32.Explain DASD,JBOD,DISK Array?Ans: DASD Direct Access Storage Device (originally introduced by IBM in 1956) is the oldest of the techniques for accessing disks from a host computer. Disks are directly accessed from the host (historically a mainframe system) and tightly coupled to the host environment. A hard drive in a personal computer is an example of a DASD system. Typically, you can view the DASD as a one-to-one relationship between a server/computer and its disk drive.JBOD: JBOD is an acronym for just a bunch of disks. The drives in a JBOD array can be independently addressed and accessed by the Server.DISK ARRAY : Disk arrays extend the concept of JBODs by improving performance and reliability. They have multiple host I/O ports. This enables connecting multiple hosts to the same disk array. Array management software allows the partitioning or segregation of array resources, so that a disk orgroup of disks can be allocated to each of the hosts. Typically they have controllers that can perform RAID (Redundant Array of Independent Disks) calculations.32.What is BCV?Ans: The most fundamental element of TimeFinder/Mirror is a specially defined volume called a Business Continuity Volume. A BCV is a Symmetrix volume with special attributes that allows it to be attached to another Symmetrix Logical Volume within the same Symmetrix as the next available mirror. It must be of the same size, type, and emulation (for mainframe 3380/3390) as the device which it will mirror. Each BCV has its own host address and Symmetrix device number.33. How SRDF works?Ans: SRDF used for Data mirroring between physically separate Symmetrix systems34. Explain FCIP, IFCP, ISCSI?Ans FCIP TCP/IP based tunneling/encapsulating protocol for connecting/extending Fibre Channel SANs. The entire FC frame is sent over IP links. iFCP Gateway-to-gateway protocol for FCP over IP. Mapping natively in IP across Fibre Channel and IP. An IP-based tunneling protocol for interconnecting Fibre Channel devices together in place of Fibre Channel switches. When iFCP creates the IP packets, it inserts information that is readable by network devices and routable within the IP network. iFCP wraps Fibre Channel data in IP packets but maps IP addresses to individual Fibre Channel ports. iSCSI Native TCP/IP protocol. An IP-based protocol for establishing and managing Connections between IPbased storage devices, hosts, and clients. No Fibre Channel content, but bridging between iSCSI and FC is possible. 35. What is WWN? Ans: WWN: All Fibre Channel devices (ports) have 64 bit unique identifiers called World Wide Names (WWN). These WWNs are similar to the MAC address used on a TCP/IP adapter, in that they uniquely identify a device on the network and are burned into the hardware or assigned through software. It is a critical feature, as it used in several configurations used for storage access. However, in order to communicate in the SAN, a port also needs an address. This address is used to transmit data through the SAN from source node to destination node.

36. What is zoing and how many types of zoning? Ans:Zone Controlled at the switch layer List of nodes that are made aware of each other A port or a node can be members of multiple zones Zone Set A collection of zones Also called zone config

EMC recommends Single HBA Zoning A separate zone for each HBA Makes zone management easier when replacing HBAs Types of zones: Port Zoning (Hard Zoning) Port-to-Port traffic Ports can be members of more than one zone Each HBA only sees the ports in the same zone If a cable is moved to a different port, zone has to be modified WWN based Zoning (Soft Zoning) Access is controlled using WWNWWNs defined as part of a zone see each other regardless of the switch port they are plugged intoHBA replacement requires the zone to be modified Hybrid zones (Mixed Zoning) Contain ports and WWNs Port Zoning Advantages: More Secure, Simplified HBA replacement Disadvantages: ReconfigurationWWPN Zoning Advantage: Flexibility, Reconfiguration, Troubleshooting Disadvantages: Spoofing, HBA replacement

37. What is flushing and how many levels? Ans: Three levels of flushing: Idle - Low I/Os to the LUN; user I/Os continue Watermark - Priority depends on cache fullness; user I/Os continue Forced - Cache has no free space; user I/Os queue With write cache enabled, all writes will enter the write cache on the owning SP, and then get mirrored to the other SP. As the write cache fills, it attempts to empty the write cache to the destination disk drives. This process is called Flushing. We have the ability to control this activity by setting watermarks for write cache, a Low and a High. Until cache fullness reaches the Low Watermark (default value = 40%), the SP is in a state called Idle Flushing. The SP will attempt to clear cache lazily and during idle periods of the array. The array is at its peak cache performance during idle flushing.To maintain free space in write cache, pages are flushed From write cache to the drivesThree levels of flushing: Idle flushingLUN is not busy; user I/Os continue Watermark processingPriority depends on cache fullness; user I/Os continue Forced flushingCache has no free space; user I/Os stall For maximum performance: provide a cushion of unused cache for I/O bursts minimize/avoid forced flushes Low & high Water mark: At the low water mark the flushing process is given a higher priority by assigning a single thread to the write cache flushing process for each scheduler cycle. As the amount of unflushed data in write cache increases beyond the low water mark higher priorities are assigned to the flushing process at regular intervals by Assigning additional threads to each scheduler cycle, until a maximum of 4 threads are assigned at the high water mark.

Forced flushing: If the data in the write cache continues to increase, forced flushing will occur at a point where there is not enough room in write cache for the next write I/O to fit. Write I/Os to the array will be halted until enough data is flushed to make sufficient room available for the next I/O. This process will continue until the forced flushing plus the scheduled (watermark) flushing creates enough room for normal caching to continue. All during this process write cache remains enabled.38. What is FC-AL?Ans: Fibre Channel Arbitrated Loop has a shared bandwidth, distributed topology, and can connect with hubs.39. What is San Copy?Ans: SAN Copy allows for data replication to heterogeneous storage arrays through Fibre Channel topology, without involving hosts, or LAN topolgies.40. SAN Toplogies?Ans: SAN Connectivity Topologies Point to Point (P-to-P) : Point to Point is a direct connection between two devices. Fibre Channel Arbitrated Loop (FC-AL) : Fibre Channel Arbitrated Loop has a shared bandwidth, distributed topology, and can connect with hubs. Fibre Channel Switch Fabric (FC-SW): Fibre Channel Switched Fabric (FC-SW) can have multiple devices connected via switching technologies. Fibre Channel Switched Fabric provides the highest performance and connectivity of the three topologies. A switched fabric provides scalability and dedicated bandwidth between any given pair of inter-connected devices. It uses a 24-bit address (called the Fibre Channel Address) to route traffic, and can accommodate as many as 15 million devices in a single fabric.41. What is cluster?Ans: Multiple server acts like single server, when one server down, user in the end will not get any effort.

42. What is JBOD?Ans: JBOD is an acronym for just a bunch of disks. The drives in a JBOD array can be Independently addressed and accessed by the Server.43. What is trespassing?Ans: If the Storage Processor, Host Bus Adapter, cable, or any component in the I/O path fails, ownership of the LUN can be moved to the surviving SP Process is called LUN Trespassing.44. What is Snapview?Ans: SnapView includes two separate types of internal data replication: Snapshots and Clones. Snapshots: Point-in-time virtual copies of LUNs. Allow for on-line back-up of databases while only using 10-20% of the source disk resources.Clones: Full Synchronous copies of LUNs within the same array. Can be used as a point-in-time, FULL copy of a LUN through the fracture process, or as a data recovery solution in the event of a failure.

45. What is replication software? What is RMSE? Ans: Replication Technology Microsoft VSS Symmetrix: Time Finder/Mirror, Time Finder/Snap, SRDF/Synchronous, SRDF/Asynchronous ECA (consistency) Clarion : Snap View clones, Snap View snapshots, SAN Copy, HP Storage Works Clones RMSE: Creates disk replicas of mission-critical information for customers running Windows on EMC Clarion storage arrays Designed for the commercial customer space Customer installable, Easy to use

46. What is vault? Ans: When problems occur, such as a power or SP Failure, the contents of write cache are copied into a special area of the first 5 drives on the array called THE VAULT.47. What is CMI how it works?Ans: CLARiiON Messaging Interface (CMI) used to communicate between SPs SP-A SP-B The mirroring insures data is protected from a single SP failure. The connection between the SPs, called the CMI, carries data and status information between SPs. On FC-series arrays, the CMI is a single connection, running at 100 MB/s. On CX-series arrays, the CMI is a dual connection, with each connection running at 200 MB/s.48. What is access logic?Ans: Access Logix is array-based software which facilities a shared-storage Environment. It will segment the storage on a CLARiiON so that hosts will only See the LUNs we intend for them to see. The generic term for this is LUN Masking, as the array is technically hiding unwanted LUNs from the hosts.49. What is HBA?Ans: HBA is any adapter that allows a computer bus to attach to another bus or channelA Host Bus Adapter performs many low-level interface functions automatically to minimize the impact on host processor performanceThe HBA enables a range of highavailability and storage management capabilities Load balance Fail-over SAN administration Storage management

50. Explain SRDF and configuration?

SRDF: It is a business tool that allows a client with symmetrix based data centers to copy their data between the sites for a number of purposesBy maintaining copies of data in different physical locations, SRDF enables you to perform the fllowing opearations by integrating with your strategies for 1.Disaster restarts, disaster restart testing, 2. Recovery from planned outages, remote backup 3.Data center migration, data replication and mobility Many different disaster recoveriesSRDF/s,SRDF/A,SRDF/DM (data mobility)4Add-on solutions SRDf/Star-Multi point replication SRDF/CG - Consistency group SRDF/AR - Automated Replication SRDF/CE - Culster Enable

SRDF: Data mirrioring between physically spearate Symmetrix systemsModes:Synchronous ReplicationSemi-synchronous replicationAdaptive Copy ReplicationAsynchronous Replication

Conectivity options:RLD: Remote Link DirectorRFD: Remote fiber directorCommunication is peer-to-peer 2 typesGigiE Remote Directors and MPC

MPCD: Multiprotocal Chancel directorSRDF conection: Uni-driectional, Bi-Directional, Dual Configaration Flexible Configuration: 1.Multiple source symmetrix to a single target symmetrix 2.Single Source symmetrix to multiple target symmetrix Switched SRDF

51. What Is MirrorView/S?Ans: MirrorView/S is a software application that maintains a copy image of a logical unit (LUN) at separate locations in order to provide for disaster recovery; that is, to let one image continue if a serious accident or natural disaster disables the other.MirrorView/S Features and BenefitsMirrorView/S mirroring has the following features:1. Provision for disaster recovery with minimal overhead 2. CLARiiON environment 3. Bidirectional mirroring 4. Integration with EMC SnapView LUN copy software 5. Integration with EMC SAN Copy software

CLARiiON MirrorView/S EnvironmentMirrorView/S operates in a highly available environment, leveraging the dual-SP design of CLARiiON systems. If one SP fails, MirrorView/S running on the other SP will control and maintain the mirrored LUNs. If the server is able to fail over I/O to the remaining SP, then mirroring will continue as normal. The high-availability features of RAID protect against disk failure, and mirrors are resilient to an SP failure in the primary or secondary storage system.Integration with EMC SnapView Snapshot SoftwareSnapView software lets you create a snapshot of an active LUN at any point in time; however, do this only when the mirror is not synchronizing the secondary image. Since the secondary image is not viewable to any servers, but you can use SnapView in conjunction with MirrorView/S to create a snapshot of a secondary image on a Secondary storage system to perform data verification and run parallel processes, for example backup.

52. What Is MirrorView/A?Ans :MirrorView/A lets you periodically update a remote copy of production data. It is a software application that keeps a point-in-time copy of a logical unit (LUN) and periodically replicates the copy to a separate location in order to provide disaster recovery, that is, to let one image continue to be active if a serious accident or natural disaster disables the other. It provides data replication over long distances (Hundreds to thousands of miles).MirrorView/A Features and Benefits:MirrorView/A mirroring has the following features:1. Provision for disaster recovery with minimal overhead 2. CLARiiON environment 3. Bidirectional mirroring 4. Integration with EMC SnapView LUN copy software 5. Replication over long distances

CLARiiON MirrorView/A EnvironmentMirrorView/A operates in a highly available environment, leveraging the dual-SP design of CLARiiON systems. If one SP fails, MirrorView/A running on the other SP will control and maintain the mirrored LUNs. If the server is able to fail over I/O to the remaining SP, then periodic updates will continue. The high-availability features of RAID protect against disk failure, and mirrors are resilient to an SP failure in the primary or secondary storage system.

53. What Is EMC SAN Copy?Ans :EMC SAN Copy is storage-system-based software for copying data directly from a logical unit on one storage system to destination logical units on supported remote systems without using host resources. SAN Copy connects through a storage area network (SAN), and also supports protocols that let you use the IP WAN to send data over extended distances.SAN Copy runs in the SPs of a supported storage system (called a SAN Copy storage system), and not on the host servers connected to the storage systems. As a result, the host processing resources are free for production applications while the SPs copy data.SAN Copy can copy data between logical units as follows:1. Within a CLARiiON storage system 2. On CLARiiON storage systems 3. On CLARiiON and Symmetrix storage systems 4. On CLARiiON and qualified non-EMC storage systems

SAN Copy can use any CLARiiON SP ports to copy data, provided the port is not being used for MirrorView connections. Multiple sessions can share the same port. You choose which ports SAN Copy sessions use through switch zoning.SAN Copy Features and BenefitsSAN Copy adds value to customer systems by offering the following features:1. Storage-system-based data mover application that offloads the host, thereby improving host performance 2. Software that you can use in conjunction with replication software, allowing I/O with the source logical unit to continue during the copy process 3. Simultaneous sessions that copy data to multiple CLARiiON and Symmetrix storage systems 4. Easy-to-use, web-based application for configuring and managing SAN Copy 54. What Is EMC SAN Copy/E?Ans :Like EMC SAN Copy, EMC SAN Copy/E is storage-system-based software for copying data directly from a logical unit on one storage system to destination logical units on supported remote systems without using host resources. SAN Copy/E connects through a storage area network (SAN), and also supports protocols that let you use the IP WAN to send data over extended distancesSAN Copy/E runs only on a CX300 or AX-Series storage system and can only copy data to CX-Series storage systems that are running San Copy.SAN Copy/E can use any CLARiiON SP ports to copy data, provided the port is not being used for MirrorView connections. Multiple sessions can share the same port. You choose which ports SAN Copy sessions use through switch zoning.SAN Copy/E Features and BenefitsThe SAN Copy/E adds value to customer systems by offering the following features:1. Incremental copy sessions from AX-Series or CX300 storage systems to SAN Copy systems located in the data center. 2. Storage-system-based data mover application that uses storage area network (SAN) rather than host resources to copy data resulting in a faster copy process. 3. Easy-to-use, web-based application for configuring and managing SAN Copy/E. 4. Software that you can use in conjunction with replication software, allowing I/O with the source logical unit to continue during the copy process

55. Explain Clariion CX Series?Ans :Disk Array Enclosure (DAE) CX family uses DAE2 with up to (15) 2Gb FC Drives FC family uses DAE with up to (10) 1 GB FC drives DAE2-ATA contains up to 15 ATA drives (Advanced Technology Attachment) Disk Array Enclosure (DAE2P) CX family only on 300, 500, and 700 series Replacement for DAE2 with code upgrade Houses up to 15 2GB FC Drives Disk Processor Enclosure (DPE) Some CX series use DPE2 that contains Storage Processors and up to (15) 2Gb FC Drives FC family uses DPE that contains Storage Processors and up to (10) 1Gb FC Drives Storage Processor Enclosure (SPE) Contains two dual CPU Storage Processors and no drives Standby Power Supply (SPS) Provides battery backup protection

56. How CMI works?Ans :CMI: CLARiiON Messaging Interface (CMI) used to communicate between SPs SP-A SP-B the mirroring insures data is protected from a single SP failure. The connection between the SPs, called the CMI, carries data and status information between SPs. On FC-series arrays, the CMI is a single connection, running at 100 MB/s. On CX-series arrays, the CMI is a dual connection, with each connection running at 200 MB/s.57. What is Vault?Ans : The vault is a reserved area found on the first 9 disks of the DPE on the FC series and the first 5 drives on a CX series system. For this reason, only the DPE needs to be kept alive in the event of a power failure. At the first sign of an event which could potentially compromise the integrity of the write cache data, that data is dumped to the vault area. It is protected there by the non-volatile nature of disk58. What is flushing and how many levels? Ans: Three levels of flushing: Idle - Low I/Os to the LUN; user I/Os continue Watermark - Priority depends on cache fullness; user I/Os continue Forced - Cache has no free space; user I/Os queue 59. Explain Meta LUNs? Ans : a metaLUN is created by combining LUNs Dynamically increase LUN capacity Can be done on-line while host I/O is in progress A LUN can be expanded to create a metaLUN and a metaLUN can be further expanded by adding additional LUNs Striped or concatenated Data is restriped when a striped metaLUN is createdAppears to host as a single LUN

Added to storage group like any other LUN Can be used with MirrorView, SnapView, or SAN Copy Supported only on CX family with Navisphere 6.5+ 60. What is Trespassing:Ans : If the Storage Processor, Host Bus Adapter, cable, or any component in the I/O path fails, ownership of the LUN can be moved to the surviving SP Process is called LUN Trespassing61. what is power path ?Ans : Host Connectivity Redundancy PowerPath Failover SoftwareHost resident program for automatic detection and management of failed paths Host will typically be configured with multiple paths to LUNIf HBA, cable or Switch fails,PowerPath will redirect I/O over surviving pathIf Storage Processor fails, PowerPath will Trespass LUN to surviving Storage Processor and redirect I/ODynamic load balancing across HBA and Fabric Not Storage Processors62. Explain FLARE Operating Environment?Ans : FLARE software manages all functions of the CLARiiON storage system. Each storage system ships with a complete copy of FLARE software installed. When you power up the storage system, each SP boots and executes FLARE software.FLARE performs provisioning and resource allocationMemory budgets for caching and for snap sessions, mirrors, clones, copies Process SchedulingBoot Management

Access Logix software is optional software that runs within the FLARE operating environment on each storage processor (SP). Access Logix provides access control and allows multiple hosts to share the storage system. This LUN Masking functionality is implemented using Storage Groups. A Storage Group is one or more LUNs within a storage system that are reserved for one or more hosts and are inaccessible to other hosts. When you power up the storage system, each SP boots and executes its Access Logix software.Navisphere Management software is a suite of tools that allows centralized management of CLARiiON storage systems. Navisphere provides a centralized tool to monitor, configure, and analyze performance. CLARiiON can also be managed as part of EMC ControlCenter, allowing full end-to-end management.63. SAN Connectivity MethodsAns :There are three basic methods of communication using Fibre Channel infrastructure Point to point (P-to-P)A direct connection between two devices Fibre Channel Arbitrated Loop (FC-AL)A daisy chain connecting two or more devices Fabric connect (FC-SW)Multiple devices connected via switching technologies64. What is a Fabric?Ans : Logically defined space used by FC nodes to communicate with each other One switch or group of switches connected togetherRoutes traffic between attached devices Component identifiers: Domain ID Unique identifier for an FC switch within a fabric Worldwide Name (WWN)Unique 64-bit identifier for an FC port (either a host port or a storage port)65. Explain Fabric Security Zoning?Ans : Zone Controlled at the switch layer List of nodes that are made aware of each other A port or a node can be members of multiple zones Zone Set A collection of zones Also called zone config EMC recommends Single HBA Zoning A separate zone for each HBA Makes zone management easier when replacing HBAs 66. Explain Types of zones?Ans : Port Zoning (Hard Zoning) Port-to-Port traffic Ports can be members of more than one zone Each HBA only sees the ports in the same zone If a cable is moved to a different port, zone has to be modified WWN based Zoning (Soft Zoning) Access is controlled using WWNWWNs defined as part of a zone see each other regardless of the switch port they are plugged intoHBA replacement requires the zone to be modified Hybrid zones (Mixed Zoning) Contain ports and WWNs Port Zoning Advantages: More Secure, Simplified HBA replacementDisadvantages: ReconfigurationWWPN Zoning Advantage: Flexibility, Reconfiguration, Troubleshooting Disadvantages: Spoofing, HBA replacement67 . Diff between Block and file ?Ans :

File Level Storage- This storage technology is most commonly used for storage systems, which is found in hard drives, NAS systems and so on. In this File Level storage, the storage disk is configured with a protocol such as NFS or SMB/CIFS and the files are stored and accessed from it in bulk. The File level storage is simple to use and implement. It stores files and folders and the visibility is the same to the clients accessing and to the system which stores it. This level storage is inexpensive to be maintained, when it is compared to its counterpart i.e. block level storage. Network attached storage systems usually depend on this file level storage. File level storage can handle access control, integrate integration with corporate directories; and so on. "Scale Out NAS" is a type of File level storage that incorporates a distributed file system that can scale a single volume with a single namespace across many nodes. Scale Out NAS File level storage solutions can scale up to several petabytes all while handling thousands of clients. As capacity is scaled out, performance is scaled up.Block Level Storage- In this block level storage, raw volumes of storage are created and each block can be controlled as an individual hard drive. These Blocks are controlled by server based operating systems and each block can be individually formatted with the required file system. Block level storage is usually deployed in SAN or storage area network environment. This level of storage offers boot-up of systems which are connected to them. Block level storage can be used to store files and can work as storage for special applications like databases, Virtual machine file systems and so on. Block level storage data transportation is much efficient and reliable. Block level storage supports individual formatting of file systems like NFS, NTFS or SMB (Windows) or VMFS (VMware) which are required by the applications. Each storage volume can be treated as an independent disk drive and it can be controlled by external server operating system. Block level storage uses iSCSI and FCoE protocols for data transfer as SCSI commands act as communication interface in between the initiator and the target.

69. Diff between Packet and Frame?Ans: A packet refers to the encapsulated unit created at the nework layer of the OSI model. One of the most commonly encountered packets is the IP packet, which contains control information such as the source and destination IP addresses, differentiated services flags and so on. Thus, a packet typically contains logical address information. A frame, on the other hand, refers to the encapsulated unit created at the data link layer. One of the most commonly encountered frames is the Ethernet frame, which contains information such as source and destination MAC addresses etc. Thus a frame typically contains physical address information. It is worth noting that a packet is encapsulated within a frame and hence the packet would always form the data part of the frame. For a transmitting host, data is first encapsulated within the packet, which is further encapsulated in a frame. This is then sent out over the physical layer as a bit stream. For a receiving host, the physical bit stream is picked up, translated into a frame and the frame headers are stripped off (decapsulated), thereby retrieving the packet, which is then further decapsulated to retrieve higher layer information.68. Hard and soft zoning? Ans: WWN zoning - WWN zoning uses the unique identifiers of a node which have been recorded in the switches to either allow or block access A major advantage of WWN zoning is flexibility. The SAN can be re-cabled without having to reconfigure the zone information since the WWN is static to the port. Port zoning - Port zoning uses physical ports to define zones. Access to data is determined by what physical port a node is connected to. Although this method is quite secure, should recabling occur zoning configuration information must be updated. 69. What is the difference between Hub and switch? Ans: A switch is much faster than a hub and reduces collisions/retransmissions. Switches send traffic only to the destination device/port, while hubs broadcast the data to all ports. If you have a choice, a switch will provide more reliable and faster transfers of data71 | TEJA SAN Q & A