IP STORAGEIP- based storage protocol known as IP Storage

-- Priyanka Patil ME(Comp)

IP Storage Protocols

• FC SAN – Used for Big enterprise– Suitable for SCSI and LAN(TCP/IP)

• FC IP- Used for small/ medium enterprise– build upon TCP, IP, Ethernet– Protocols available for transmitting storage data

traffic over TCP/IP are as follows:1. iSCSI-: internet Small computer system interface2. iFCP- : intenet Fiber channel protocol3. FCIP- : FC over IP

iSCSI

• Transmit SCSI protocol over TCP/IP• SCSI cable replaced by TCP/IP Ethernet connection• iSCSI is installed in OS as device driver• Traditional Ethernet card: separate iSCSI device driver

installation( load on CPU)– Used for low or average performance requirement

• Now , iSCSI + HBA( hardware) :( relives load on CPU)– Which gives high performance therefore used for

application where high performance is required

SCSI over TCP/IP Ethernet

iSCSI benefits:•FC SAN’S storage capacity is made available with iSCSI to FC gateway•Booting from diskless node is possible

iFCP and mFCP• Used on production environment• iFCP realise mapping of FCP on TCP/IP• iFCP is used in IP/ Ethernet network infrastructure

(reduces no. of FC devices)• To do so, F-port, FL-port are needed on LAN switches• mFCP to iFCP is used to connect large network• mFCP: metro FCP: works on UDP/IP• iFCP : works on TCP/IP

iFCP (cont..)

• To implement services like Zoning & name services use appropriate gateway & switch

mFCP & iFCP are complex protocols gives compatibility issues due to dependency on other devices.

mFCP & iFCP components need testing & implementation effort by manufacturer

FCIP & FC to iSCSI is better option

iFCP

FCIP

• Removes distance limitation of FC• Covers larger distance suitable for big enterprise• Distance between Production site and Backup site is

more in this case WAN or tape backup techniques were used

• Now , FCIP is alternate technique is present to take backup

FCIP(cont..)

• It is a tunnel between two FC islands connected with each other over TCP/IP

• Creates point to point connection between FC SAN’s tunnels

• It Sends FC frames into TCP/IP packets through tunnel

• Provides data encryption with the help of IPsec over IP routers

FCIP

iSNS internet storage name service

• Services that allow to get properties of end device in IP network

• iSNS is client server based application• Client registers with server in the network• Every device’s join and leave information is

updated to client present in the network• It is integrated service of iSCSI, iFCP

FC IP Storage

Efficient than IP storage Less efficient

Uses FCP Uses TCP/IP

Less protocol overhead Higher protocol overhead

Reliable transmission techniques

Unreliable transmission techniques

IP storage advantages and disadvantages

Advantages DisadvantagesHas common network for LAN, WAN,MAN,SAN

Lack of interoperability among different component

Use of TCP/IP gives standardization & maturity

CPU cycles are heavily used for storage

People have more knowledge about TCP/IP than FC

TCP/IP has higher network overhead

No distance limit Not designed for bulk dataLow hardware cost than FC Ethernet switches have

high delay

IP storage will be useful for average application

Infiniband switch• Defines copper & fiber optics cables with maximum length• To provide remedy for drawback of PCI bus• Replaces PCI bus with serial network• In single data center different IO techniques are use like

FC,ethernet,SCSI– Infiniband acts as communication medium for those

who are in the network– Forwarding and receiving data packets from source to

destination– Provides features such as flow control,zoning, etc

Infiniband (cont..)

• Fast interconnect for IPC within parallel cluster network

• Supports full duplex communication• HCA: host channel adapters– Acts as bridge between infiniband n/w and the system bus

to which CPU & RAM are connected• TCA: target channel adapters– Connect infiniband n/w & peripheral devices via SCSI,FC,

ethernet

VIA- Virtual Interface Architecture

• It is integral part of infiniband switch• Provides fast & efficient data exchange between

applications running on different computers• For this n/w should have low latency & low error rate• Due to this VIA is used over shorter distance within

data center or building• VIA reduces complexity – acts as a bridge between application & network card so it

bypasses OS while exchanging data

• Establish Virtual interface:– Reserve common memory on both computers which will

be used by application & local network card to exchange data

– When application fills with data it announces door bell for sending it in the queue

– VI hardware then reads the data from common memory and transmit it to second computer

– An application on one computer communicate with VI NIC of other computer by bypassing OS

– VI kernel : to add and delete VIs

References

• IP storage “ Storage Network Management and Retrieval” Vaishali kumar, Nilima Dongre “ Wiley Precise Textbook series” 2016