Symmetrix Question And Answers-1

1. What is the FAN-IN and FAN-OUT ratio of DMX-4? 2. How many members can contain in one meta? 3. How many LUN IDs available per port? 256 4. What Dynamic LUN addressing? 5. How do you add a new member to the existing Meta?

6. What are the RAID levels DMX-4 Supports?

7. How do you check the back-end Operations on Symmetrix Array? 8. What are the service states of a device?

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Symmetrix device service state. Possible values are: Normal - All mirrors are functioning properly Degraded - A mirror has failed Failed - An unprotected device has failed 9. What are the status of a device? Device status. Possible values are: Ready Not Ready Write Disabled N/A 10. How do you reserve the devices? Reservations managed by the PERSISTENT RESERVE IN and PERSISTENT RESERVE OUT SCSI commands. These commands allow for more control over reservations, and offer more possibilities. I'll call these "new style" reservations. They are to eventually replace old style reservations, but at the moment they are not that widely used. A Symmetrix device will only accept these commands when the "SCSI3_persist_reserv" flag is enabled for the particular device. What Solutions Enabler calls "Exclusive" reservations, are old style reservations. These are visible with the command "symdev -sid xxx list -resv". "PGR" reservations are new style reservations. These are visible with the command "symdev -sid xxx list -pgr".(*) 11. How do you check the free space by Disk group and Array as whole? symdev -sid <symid> list noport 12. How do you check the particular disk is connected to which DA Port and it is resides in particular DAE? symdisk -sid 120 list 13. How do you check the particular device is connected to which Host? symmaskdb list assignment -dev 0001:000A 14. How do you check the total allocated storage of a Host? symmaskdb list capacity -host api140

Symmetrix Question And Answers-1

15. Host is unable to see the storage, what may be the problem?

Confirming HBA logins Checking adapter status Checking FA port settings Confirming device mapping Confirming device masking Setting up a host for storage systemsetc

16. How do you list the Hosts which are connected to particular director port? symcfg list -connections sorthost -sid 120 dir8a p 0 17. How do you check the number of storage bays connected to the system bay and number of disks in each storage bay? symcfg -sid 2705 list -env_data 18. How do you check the devices which are mapped to FA but not masked to any host? symmaskdb -sid ### list no_assignment (Where ### is the last 3 digits of the Symmetrix serial number) To list a specific FA port, 8AA for example, run: Symmaskdb list no_assignment -sid ### -dir 8a -p 0 19. How many mirror positions RAID-1 and RAID-5 will occupy? In the world of Symmetrix, a mirror-position is a device in the system that a segment of cache refers to. When a write occurs, it is acknowledged by cache, then the system will deliver the write to all of the necessary mirror-positions. If it is a 2 Way Mirror (RAID1) it will write to mirror-position 1 (first RAID1 device) and mirror-position 2 (second RAID1 device).

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20. How do you increase the mirror positions? Increase/decrease of EMC Symmetrix BCV mirror sets to provide additional copies of data You can have upto 8 BCV to a standard volume but not at the same time You can have only two BCV attached to a standard volume and u can have 8 clone attached to the standard volume at the same time, again there are two types of BCV's protected BCV and unprotected BCV as any standard device will have four mirror positions 1. first mirror position is the device itself 2. second mirror position is taken by RAID so a typical SYMM. device wil always use two mirror positions one for the device and second for the raid device(mirror) you cannot break this and use them as two seperate devices with that said two out of four is always used by any SYMM. device the remaining two mirror positions can be used for two purposes a. we can have a local BCV device attached to it in which case its 2 BCV max at the same time -because only two mirror positions are available b. we can have an SRDF device in remote SYMM. two different symmetrix that is concurrent srdf

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3. we can have one BCV and one SRDF - one local copy and one remote copy there are the combinations available there is a fourth type called CLONE which will not use the mirror position so we can clone a standard device into 8 clones to 16 clones at a time without sacrificing any mirror positions. we cannot have 3 BCV's for a standard device because symmetrix does not support unprotected standard device 21. What is FA Port Flag and how do you set the FA port flags? You can set a configuration flag that allows different host types to share a single director FA port, even though different hosts may require different port settings for their interface protocol. Setting this flag sets an entry in the VCMDB to hold connection protocol information on the specified host type that may differ from the current Fibre protocol setting on the director. You can use this feature in conjunction with the LUN offset/skip feature to allow different host types to share access to the same FA port. The following command enables heterogeneous on FA director 16A, port 0, for a Solaris type host: symmask sid 814 dir 16A -p 0 set heterogeneous on SOLARIS wwn 20000000c920b484 The following command disables heterogeneous for the Solaris type host: symmask sid 814 dir 16A -p 0 set heterogeneous off SOLARIS wwn 20000000c920b484

22. Can windows, Linux, Solaris share the same FA in DMX? Refer to answer 21 23. What are the External locks and how to check? Any Symmetrix configuration command requires a lock on the Symmetrix, to prevent conflicting operations. Once your configuration operations are complete (or if the operation is cancelled), it may take several minutes before the lock is released on the Symmetrix. If you try a subsequent configuration command before the lock is released, an error message is displayed indicating that the lock is currently held. Wait a few minutes and retry. If the lock is still not released, use Solutions Enabler SYMCLI to release the lock symcfg -sid 15 list -lockn all to relase the lock symcfg -sid 1234 -lockn 15 release -force 24. How to monitor performance of EMC Symmetrix?

Symmetrix Question And Answers-1

In order to compare the performance metrics of Symmetrx (and DMX) arrays in CCStorage we must first make sure the prerequisites are set correctly. CommandCentral Storage collects monitoring data for Devices, Disks, Directors (FA), and Ports only. In CCStorage, The Device Configuration must have Enable Monitoring checked for each array. NOTE: Monitoring is NOT enabled by default for Symmetrix arrays in CommandCentral Storage. Now, we can compare how CCStorage presents the data from SymCLI. NOTE: In CommandCental Storage, monitoring interval to collect Symmterix performance data is 30 minutes. At the interval of 30 minutes, CommandCentral Storage executes the SYMCLI commands and collects performance data. i=60 and c=2 means that symstat command display performance data for the interval of 60 seconds.

Collectors for Symmetrix Devices Collector Name SymCLI Command to Collect Data Cache Read Hit Ratio symstat -i 60 -c 2 -sid <sid> -type backend Cache Write Hit Ratio symstat -i 60 -c 2 -sid <sid> -type backend Device Capacity symdev -sid <sid> list I/O Read per Second symstat -i 60 -c 2 -sid <sid> -type backend I/O Write per Second symstat -i 60 -c 2 -sid <sid> -type backend KB Read per Second symstat -i 60 -c 2 -sid <sid> -type backend KB Write per second symstat -i 60 -c 2 -sid <sid> -type backend Percentage Sequential Reads symstat -i 60 -c 2 -sid <sid> -type backend

Collectors for Symmetrix Disks Collector Name SymCLI Command to Collect Data I/O Read per Second symstat -i 60 -c 2 -type DISK -sid <sid> I/O Write per Second symstat -i 60 -c 2 -type DISK -sid <sid> KB Read per Second symstat -i 60 -c 2 -type DISK -sid <sid> KB Write per Second symstat -i 60 -c 2 -type DISK -sid <sid>

-disk ALL,ALL,ALL -disk ALL,ALL,ALL -disk ALL,ALL,ALL -disk ALL,ALL,ALL

Symmetrix Question And Answers-1

Collectors for Symmetrix Director (FA) SymCLI Command to Collect Data symstat -i 60 -c 2 -type cache -sid <sid> -dir ALL symstat -i 60 -c 2 -type prefetch -sid <sid> -DA ALL symstat -i 60 -c 2 -type prefetch -sid <sid> -DA ALL

Collector Name

Cache Read Misses per Second Prefetch Tracks per Second Prefetch Tracks Used per Second

Prefetch Tracks Unused per Second symstat -i 60 -c 2 -type prefetch -sid <sid> -DA ALL

Collector Name Port Status I/O per Second KB per Second

Collectors for Symmetrix Ports SymCLI Command to Collect Data symcfg -sid <sid> -SA ALL -port list symstat -i 60 -c 2 -type port -sid <sid> -dir all -port all symstat -i 60 -c 2 -type port -sid <sid> -dir all -port all

To compare any of the performance metrics above you will need to do the following. 1. Run the appropriate SymCLI command at 30 minute intervals for the time frame you want to compare. 2. Create a Custom Report in CommandCentral Storage for the Array and attributes you want to comapre for the same time period

25. How do you check performance statistics of a particular director port?

Collectors for Symmetrix Ports Collector Name Port Status I/O per Second KB per Second SymCLI Command to Collect Data symcfg -sid <sid> -SA ALL -port list symstat -i 60 -c 2 -type port -sid <sid> -dir all -port all symstat -i 60 -c 2 -type port -sid <sid> -dir all -port all

To compare any of the performance metrics above you will need to do the following. Run the appropriate SymCLI command at 30 minute intervals for the time frame you want to compare. Create a Custom Report in CommandCentral Storage for the Array and attributes you want to comapre for the same time period. 26. What are the logs available at host-end and on symmetrix array?

Symmetrix Question And Answers-1

27. How do you monitor the real time events on symmetrix array with example? symevent list -sid 0207 -start 12:00 -end 15:00 v Symmetrix ID: 000192600207Time Zone : EST Event at Mon Dec 29 13:00:10 2008: Reporting Director : RF-7H Source : Symmetrix Category : RDF Severity : InformationalNumeric Code : 0x000d Event Code Symbol : RDF_SIM_MESSAGE Description : The RDF subsystem initiated a SIM message to a Symmetrixremotely-attached via RDF links Event at Mon Dec 29 13:01:38 2008: Reporting Director : FA-7E Source : Symmetrix Category : RDF Severity : InformationalNumeric Code : 0x0018 Event Code Symbol : RDF2_DEVICE_NR Description : One of the RDF2 devices was found to be Not Ready 28. What are all the logs available in Symmetrix? Symmetrix Activity Log: Overview A Symmetrix maintains a log file of activity with all connected hosts. For the most part, these log file entries are generated by applications performing control operations that affect the status and accessibility of the Symmetrix or its devices.

The activity may come from the Service Processor, SYMCLI commands, SYMAPI applications, ControlCenter itself, and other user or vendor applications. The Symmetrix Activity Log command allows you to view these log file entries from the ControlCenter Console. Symmetrix Activity Log functionality is only available with Enginuity 5x68 or later. Viewing a Symmetrix Activity Log Click the Monitoring view.

Symmetrix Question And Answers-1

Select a Symmetrix array. From the right-click menu select Activity Log. Or from the Log menu, you can select Symmetrix, Activity Log. The Symmetrix Activity Log dialog box appears.

29. How do you check the audit logs on symmetrix array? Data is written to a common audit file during Symmetrix control operations initiatedby host applications. The common audit log correlates activity from all hosts into onefile that is stored in the Symmetrix File System (SFS).The symaudit command enables the examination and filtering of the common auditlog file for a specified Symmetrix array. The audit log resides on the Symmetrix arrayand currently has a maximum size of 40 MB. Once the 40 MB limit is reached, the logbegins to overwrite itself. You do not have to do anything to maintain this file, unlessyou want to capture records before the circular 40 MB space recycles.Use the following actions to parse or monitor the audit log contents a. show Displays details about the audit log itself for a specific Symmetrix array,including: the total range of records, the date/time range, and the starting recordnumber. b. list Lists details about the requested records in either a brief or verboseformat. The range of records to extract can be filtered by one or all of thefollowing: record number, record count, date/time, functional area, controlaction, vendor ID, application ID, hostname, username, and device acted upon. c. monitor Monitors the Symmetrix array for new audit log data in realtime

symaudit show -sid 0207 symaudit list -sid 0207 -start_time 01/02/2009:12:00:00 -end_time01/02/2009:12:15:00 v

30. What is Read Hit and Write Miss? Read hit: The information is supplied by the current cache. No state change Read miss: The data is read from main memory Write hit: on hits it writes to cache and then main memory Write miss: it write to main memory when cache is disabled on array 31. What is the purpose of bin file in SAPAPI database?

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BIN file holds information on SRDF configurations, total memory, memory in slots, serial number of the unit, number of directors, type of directors, director flags, engines, engine ports, front end ports, back end ports, drives on the loop, drives on the SCSI bus, number of drives per loop, drive types in the slots, drive speeds, volume addresses, volume types, metas, device flags and many more settings. Any ongoing changes in the environment related to hardware upgrades, defining devices, changing flags, etc is all accomplished using BIN file changes BIN file changes can be accomplished 3 ways BIN file change for hardware upgrades is typically performed by EMC only BIN file change for other changes that are device, director, flags, metas, SRDF configurations etc is either performed through the SYMAPI infrastructure using SymCLI or ECC (Now Ionix) or SMC (Symmetrix Management Console) by the customer. (Edited based on the comments: Only some changes now require traditional BIN file change, typically others are performed using sys calls in enginuity environment) 32. What are the services of symcli?

33. By using what symcli command we can check the HBA details and physical details? symmask list hba 34. How to write disable and enable a device? symdev sid xxxx write_disable [SymDevName] and to write enable a deivce as follows symdev sid xxxx rw_enable [SymDevName

34. How to find devices belonging to a given disk using symdisk command? List all drives in a box with their corresponding slices: symdisk -sid xxx -v -hypers list List slices of a given drive:

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symdisk -sid xxx show XXY:KW 2) find devices mapped on at least a single path symdev -sid xxx -firstport list 3) find masked devices symmaskdb -sid xxx list database