Symmetrix DMX Interview Q and A

8/13/2019 Symmetrix DMX Interview Q and A

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Symmetrix DMX - Possible Questions for Interview

Can you explain about DMX Architecture

Can you briefly explain about symmetrix series pro!ucts

Symmetrix 8000/4 was the first symmetrix to introduce a dual bus arcitecture, providingredundancy in the path to memory.

Symmetrix D!800 is an incrementally scalable, high"end storage array which featuresmodular dis# array enclosures.

Symmetrix Direct atrix $rchitecture is storage array technology that employs a matrix ofdedicated serial point"to"point connections instead of traditional buses or switches.

Symmetrix D!% is a channel director specification for the D! with faster processors and

newer components.

Symmetrix D!"& and D!"4 are the latest technology using redundant global memory and

largest capacity.

Can you explain "n#inuity release co!e $%%&'%('$)

'( represents the D!&/4 )ardware(& represents the microcode family

(* represents the field release level to the microcode

'8 represents the field release to the service processor code

'% +Symm4, '' +Symm', ' +D!/D!%, '( +D!&/4, '8 +-$!.

*ow many Cache !irectors+ ,ront-en! !irectors an! ac.-en! !irectors we can

use in DMX-/

ache Directors + 4 in to 8 ax.

ront"end Directors + up to % max.

1ac#"end Directors + in to 8 ax.

0hat are the !ifferent types of ,ront-en! !irectors an! the purpose of each one

2S3 52$6 7 for mainframe attachment and SD family lin#s

93 526 7 provides the industry:s highest performance connectivity 3ption for the

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Bp to eight power supplies, each of having a dedicated 1attery 1ac# Bp511B6

B service processor with C- 5#eyboard, video screen and mouse6 and dedicated B;S.

>hree cooling fan assemblies 5each containing & fans6.

Storage 1ay omponents7

%0 or %40 dis# drives per storage bay2ach Drive 2nclosure 5D26 includes7

>wo lin# control cards 5A6.

edundant power supplies with 11Bs to provide standby power.>he D!"4 storage bay has % power =ones with independent power cables, each =one capable

of powering the fully configured storage bay.

>he storage bay can be populated with various combinations of currently available D! one"

inch low"profile 4


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*ow !o you calculate number of cylin!ers for 278 9 5:;

aximum device si=es by 2nginuity version

2nginuity version7HHHHHHHHHH71s7HHHHHHH7@As7HHHHHH7o calculate the number of cylinders 5for pre"Symmetrix D!6, use either of the following7

bloc#s J *0 or 5si=e in megabytes6 x %.&&&

>o calculate the number of cylinders 5for Symmetrix D! and Symmetrix -"ax arrays6, use

the following7 cylinder + ' trac#s? each trac# is 4 C1, ' x 4 trac#s + .*&( 1 for each

cylinder

0hat is the maximum hyper sihis feature will automatically selects and assigns the AB 9Ds to the devices while device

mapping to the port 9nstead of manually assigning address to the device while mapping

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*ow !o you a!! a new member to the existin# Meta

add dev !!!! to meta !!!!, protectHdata+>B2, bcvHmetaHhead+!!!!?

or for multiple ranges7

add dev !!!7!!! to meta !!!!, protectHdata+>B2, bcvHmetaHhead+!!!!?

0hat is strippin# an! what is Concatenatin#

Stripped eta Devices7eta device addressing by striping divides each eta member device into a series of stripes,

addressing a stripe from each device before advancing to the next stripe on the first device.

Ehen writing to a striped volume, eual si=e stripes of data from each participating drive arewritten alternately to each member of the set.

oncatenated eta Devices7

oncatenated devices are volume sets that are organi=ed with the first byte of data at thebeginning of the first device. $ddressing continues to the end of the first device before any data

on the next device is referenced. Ehen writing to a concatenated device, the first meta device

member receives all the data until it is full, and then data is directed to the next member and soon

0hat are the DMX-/ supporte! !is. types+ no' of !is.s an! maximum capacity

drives, iSS9 drives and lash drives

' drives per D$2

%0 drivers per age

%40 drives per Storage 1ay%400 drives per array 9f total of 0 storage bays connected

aximum storage capacity is ;1.

riefly explain the DMX-/ supporte! Device types

Standard Devices7 $ Symmetrix device configured for normal Symmetrix operation under a

desired protection method 5such as $9D",$9D"S, and SDL6.


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SD Devices 5, % and %6 Devices configured as D or D% to support SD

operations. is source device for SD operations

% is target device for SD operations

% is used for multi hop SD operations

-irtual Devices7 $ host"accessible device containing trac#"level location information 5pointers6,

which indicates where the copy session data is located in the physical storage. Device copies usevirtual devices to support >imeinder/Snap operations. -irtual devices consume minimal

physical dis# storage, as they store only the address pointers to the data stored on the source

device or a pool of save devices.,

Save Devices7 Special devices 5not mapped to the host6 that provide physical storage space for

pre"update images or changed trac#s during a virtual copy session of >imeinder/Snap

operations.

Device as#ing 5-6Devices7 Symmetrix devices that have been mas#ed for visibility to

certain hosts. >he device mas#ing database 5-D16 holds device mas#ing records andtypically resides on a %4 or 48 cylinder dis# device..

D- Devices7 $ non"user"addressable Symmetrix device used by the Symmetrix 3ptimi=er totemporarily hold user data while reorgani=ation of the devices is being executed. >ypically, it is

used by the 3ptimi=er in logical volume swapping operations.

0hat is =ault !rives an! *ot Spare

-ault Drivers7 $t the time of emergency shutdown of an $rray, what ever the data in cachememory will be destaged/saved on temporary drives called vault drives

)ot Spare7 $t the time of physical drive failure hot spare drives will ta#e place

0hat is Preview+ Prepare an! Commit while usin# Symconfi#ure comman!

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>he preview argument verifies the syntax and correctness of each individual change defined, and

then terminates the session without change execution.

>he prepare argument performs the preview chec#s and also verifies the appropriateness of the

resulting configuration definition against the current state of the Symmetrix array? the argument

then terminates the session without change execution

>he commit argument completes all stages and executes the changes in the specified Symmetrix

array

0hat are the possible !evice service states an! !evice status states

Device Service States 7 ormal, ailed and DegradedDevice Status States 7 eady, ot eady and Erite Disable.

*ow !o you reserve the !evices

symconfigure "sid !!!! "f createdev.cmd "expire expiration date"owner myself "comment Mthisdevices are reserved for SD activityM reserve

*ow !o you create the Dis. 9roups

Ee can not create Dis#


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-erify the available free space in the symmetrix array

symconfigure "sid Symm9D N"v O "freespace N"units cylinders O 1PP list

symdis# "sid MSym9DM list "dis#Hgroup M


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map dev %ca to dir (d70, lun+0&?

2xecute the commandfile using symconfigure with the preview, prepare and commit options.Symconfigure "sid 4%8% "f ommandfile.txt "v "noprompt commit

as# the devices to the host )1$ and refresh the sym configurationsymmas#db "sid MSym9DM "wwn 0000000c*&f%cf "dir (d "p 0 add devs %ca "nop

Symmas# "sid MSymiDM "refresh

escan the dis#s and refresh the powerpath or reboot the server to get the assigned devices at

host"end

*ow !o you chec. particular !evice #eometry

symdev "sid !!!! show dev 00%

*ow !o you chec. the particular !evice is connecte! to which *ost

symmas#db "sid !!!! list assignment "dev 00%c

0hat are the steps for stora#e reclamation

Bnmas#ing

Erite Disable

Bn"mappingDissolve meta

Deleting hypers

. Bnmas#ing devices from the hostsymmas#db "sid 4%8% "wwn 0000000c*&f%cf "dir (d "p 0 remove devs %ca

%. efresh the Symmetrix $rraySymmas# "sid 4%8% "refresh

&. Erite Disable the devices before unmapping from the Director portsymdev "sid 4%8% writeHdisable %ca "sa (d "p 0 "noprompt

4. reate a cmd/txt file

Bnmap dev %ca from dir all7all?

'. ;erform preview operation using symconfigure command

Symconfigure "sid 4%8% "f unmap.txt "v "nop preview

. ;erform prepare operation using symconfigure command

Symconfigure "sid 4%8% "f unmap.txt "v "nop prepare

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convert meta !!!!, config+striped, stripeHsi=e+*%0, protectHdata+>B2,

bcvHmetaHhead+!!!!?

*ost is unable to see the stora#e+ how !o you troubleshoot

hec# that the host is logged in to the $rrayhec# that the cable connectivity status by logging in to the hosthec# that the )1$ drivers are properly configured

hec# the Qoning table by logging in to the switch

hec# that the devices status in $rrayhec# the -D1 for mas#ing information, etc..

0hat is 3hin Provisionin#

>hin provisioning is a method of optimi=ing the efficiency with which the available space isutili=ed in storage area networ#s. >hin provisioning operates by allocating dis# space in a

flexible manner among multiple users, based on the minimum space reuired by each user at anygiven time.

*ow !o you create thin pools an! thin !evices

reating >hin ;oolsreating Data devs and added these Data devs to >hin ;ools

reating >D2-s and bind these >D2-s to >hin ;ool

$ssign >D2-s to host.

"xplain step by step proce!ure to setup new host

Aet us assume cable connectivity is done properly

9nstall )1$ drivers in host.9nstall ;ower path if reuired.

hec# that the )1$ ports are showing online

reate =oning at switch end.

hec# that this host is logged in to the Storage arrayreate AB/hypers in storage array

orm meta devices if reuired

ap the devices to the $ port.as# the devices to the host hba 5wwn6.

efresh the $rray to affect the changes.

*ow !o you chec. the faile! components in Symmetrix Array

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Symcfg "sid '0 list "envHdata "serviceHstate failed

*ow !o you chec. the faile! !is.s in the Symmetrix Array

Symdis# "sid !!!! list "failed

0hat is the purpose of 9ate >eeper !evice

Aow"level 9/3 commands executed using S@A9 are routed to the Symmetrix array by a

Symmetrix storage device that is specified as a gate#eeper.

>he gate#eeper device allows S@A9 commands to retrieve configuration and status

information from the Symmetrix array without interfering with normal Symmetrix operations.>he gate#eeper must be accessible from the host where the commands are being executed.

*ow many #ate .eeper !evices are re?uire! per Array

9t depends on the Symmetrix management applications using in management servers,$s per 2 recommendations gate#eepers are reuired per management host using symcli

*ow to list hosts an! their "MC re#istere! software+ usin# Solutions "nabler

Symcfg "sid !!!! list "applications

0hat is =CMD an! how !o you ta.e the bac.up

>he device mas#ing database 5-D16 holds device mas#ing records and typically resides on a

%4 or 48 cylinder dis# device..

Symmas#db "sid !!!! bac#up "f filename

*ow !o you list the *osts which are connecte! to particular !irector port

Symmas#db "sid !!!! list database "dir !! "p !

*ow !o you chec. the number of stora#e bays connecte! to the system bay an!

number of !is.s in each stora#e bay

Symcfg "sid !!!! list "envHdata

*ow !o chec. the !evices which are not mappe! an! mas.e!

Symdev "sid 4%8% list dev "noport

*ow !o you chec. the !evices which are mappe! to ,A but not mas.e! to any

host

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Symmas#db "sid %& list noHassignment "dir $AA "p $AA

*ow !o you chec. the lo#in hosts in the Symmetrix Array

Symmas# "sid 4%8% list logins

*ow to !isplay an! set the Symmetrix metrics

Symcfg "sid !!!! "S$ all list "v

Set Symmetrix atricame+atric-alue

*ow !o you chec. the confi#ure! environmental variables

Symcli "def

Can win!ows+ 5inux+ Solaris share the same ,A in DMX

@es, if they share the same port flags

0hat are the Symmetrix "xternal loc.s an! how to chec. an! release

Symmetrix external loc#s are used by S@$;9 5loc#s 0 to '6 and also for applications assigned

by 2 5R'6 to loc# access to the entire Symmetrix arrayduring critical operations

Ee can chec# the external loc#s by giving the below command

symcfg "sid !!!! list "loc#n

Ee can chec# the external loc#s by giving the below commandsymcfg release "sid "loc#n ' "force

*ow to monitor performance of "MC Symmetrix

*ow !o you chec. the cache activity of front-en! !irectory

symstat "sid 4%8% "type cache "i ' "c 4 "sa all

*ow !o you chec. the I@4 re?uests an! throu#hput of selecte! !is.

Symstat "sid 4%8% "type dis# "i ' "c & "dis# %a,,'

0hat are the available performance types in SMS3A3 comman!

2B2S>S7 eports 9/3 reuests and throughput for selected devices, directors, or SD/$

sessions. 5>his is the default type? if no type is specified 2B2S>S is used.61$C2D7 eports bac#"end 9/3 reuests and throughput for selected devices.

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uality of Service 5oS6 allows more flexibility in managing Symmetrix system:s performance.

1y increasing the response time for specific copy operations on selected devices, we can increase

the overall performance of the other Symmetrix devices.

>he oS 5uality of Service6 feature allows us to adTust the data transfer pace on specified

devices, or devices in a device group, for certain operations.

>he contention for cache access can be uality of service managed by the least recently used

5AB6 ring partitions in the Symmetrix cache.

Ee can control the priority service time of devices and control cache partitions for different

device groupings.

0hat is the purpose of Symmetrix Chan#e 3rac.er

>o measure changes to data on a Symmetrix volume or group of volumes.

hange >rac#er data is often used to analy=e and design >imeinder and Symmetrix emoteData acility 5SD6 configurations.

hange >rac#er 5Deltaar#6 session must be created using the symchg create command. >he

symchg mar# command is then used to perform a timestamp and mar# the selected area of dis#storage occupied by a data obTect using a Deltaar# bitmap

0hat is Dynamic Cache Partitionin#

$ oS feature, dynamic cache partitioning allows the $dministrator the means to dynamicallycontrol the cache area si=e, servicing a given device group 9/3, by defining flexible partitions

through cache memory.

Dynamic ache ;artitioning divides the cache memory into multiple partitions with uniue

names and their device path assignments.

;artition areas can be made static or dynamic in si=e. >he dynamic partitioning provides

flexibility to the amount of floating memory that can be allocated with a high and low

watermar#. >his allows memory resources to be temporarily donated to other partitions when

needed.

>he symos command allows you to create partitions for different device groupings in addition

to the default partition that all devices belong to initially. 2ach partition will have a target cache

percentage as well as a minimum and maximum percentage. 9n addition, you can donate unusedcache to other partitions after a specified donation time.

0hat are the lo#s available at host-en! an! on symmetrix array

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)ost"end logs are available in USymapiUlog folder

2vent logs and $udit logs in symmetrix array

*ow !o you monitor the real time events on symmetrix array with example

>o monitor real time 00 event records with 00 seconds interval in the symmetrix arraySymevent "sid 4%8% monitor "i 00 "c 00 "warn/"error/"fatal

*ow !o you trac. the history of events on symmetrix array with example

>o list all events in symmetrix array

Symevent "sid 4%8% list

>o list specific period of time events in event logs

Symevent "sid 4%8% list "v "start *700 "end (700

*ow !o you chec. the au!it lo#s on symmetrix array

>o show the details about audit log it self.Symaudit "sid 4%8% show

>o list the audit log records of specific period of time.Symaudit "sid 4%8% list "v "startHtime (/7*700 "endHtime (/70700

>o monitor the real time audit logs 00 records with &0sec interval.symaudit "sid 4%8% monitor "i &0 "c 00

0hat is Symmetrix AC5

>o create access control list on symmetrix array to implement host level or user level security.

"xplain step by step to setup the access controls on symmetrix array

reate $ccess


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reate $ccess ;ools7

5reate a command file with the following entries6

reate accpool $ccess;oolame?52xecute the command file6

Symacl "sid 4%8% commit "file McommandfileM

$dd devices to the access pool

5reate a command file with the following entries6

$dd dev StartDevame72ndDevame to accpool $ccess;oolame?52xecute the command file6

Symacl "sid 4%8% commit "file McommandfileM


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9t is a database file in the host which stores the symmetrix array:s configuration data. an be

used to get the configuration data offline.

*ow !o you prepare the Stora#e Capacity plannin# reports by host wise

. 1y using 2 ontrol enter%. 1y using symcli commands symcfg and symdis#Symcfg "sid 4%8% list "connections "capacity

opy and past the output of the above command in excel file and format according to the

reuirement.3r

Symdis# "sid 4%8% list "byHdis#group

opy and past the output of the above command in excel file and do the format according to thereuirement.

y usin# what symcli comman! we can chec. the *A !etails

Symin hba "fibre

0hat are the business continuity tools for symmetrix array

;ower path " host end>imeinder " local replication

SD " emote eplication

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Symmetrix DMX Interview Q and A