Symmetrix DMX Possible Interview Questions

By | February 20, 2017

Can you explain about DMX Architecture? 
The Symmetrix DMX features a high-performance, Direct Matrix Architecture (DMX) supporting up to 128 point-to-point serial connections. Symmetrix DMX technology is distributed across all channel directors, disk directors, and global memory directors in symmetrix DMX systems.

Can you briefly explain about symmetrix series products?
Symmetrix 8000/4 was the first symmetrix to introduce a dual bus arcitecture, providing redundancy in the path to memory.
Symmetrix DMX800 is an incrementally scalable, high-end storage array which features modular disk array enclosures.
Symmetrix Direct Matrix Architecture is storage array technology that employs a matrix of dedicated serial point-to-point connections instead of traditional buses or switches.
Symmetrix DMX2 is a channel director specification for the DMX with faster processors and newer components.
Symmetrix DMX-3 and DMX-4 are the latest technology using redundant global memory and largest capacity.

Can you explain Enginuity release code 5773.79.58?
57 represents the DMX3/4 Hardware
73 represents the microcode family
79 represents the field release level to the microcode
58 represents the field release to the service processor code
52 =Symm4, 55 =Symm5, 56 =DMX/DMX2, 57 =DMX3/4, 58 =VMAX.

How many Cache directors, Front-end directors and Back-end directors we can use in DMX-4?

Cache Directors = 4 Min to 8 Max.

Front-end Directors = up to 12 max.

Back-end Directors = 6 Min to 8 Max.


What are the different types of Front-end directors and the purpose of each one?

ESCON (EA)         : for mainframe attachment and SRDF family links

FICON (EF)           : provides the industry’s highest performance connectivity Option for the mainframe.

Fibre (FA/DA)      : Connectivity option for open systems direct and SAN Attachment, and can be used for SRDF family remote Replication links.

iSCSI (SE)              : Provides the industry’s first high-end Iscsi Implementation.

GigE (RE)              : for SRDF family replication with compression support.


Explain Rule 17 in DMX?

Possible answers:

Rule of 17 ensured that FAs being used for host connectivity were in different power zones.

The rule of 17 is simply a way to make sure that the paths you connect your host to are not running on the same director, but one physically far away from it.

The original Rule of 17 was put into place to ensure that there was a path on each bus (odd and even).The bus architecture went away in DMX-1 ( Symm6).  But we had 2 power zones; one zone for directors 1-8, and another zone for directors 9-16.  So the Rule of 17 still had value.

but DIR 3 (odd) and DIR 4 (even) reside on different buses yet in the same power zone, so even if you had your host connected to 3 and 4 ..if that power zone went down ..Your hosts went down.

What are the Management Tools for DMX?

Symcli (Symmetrix Command Line Interface)

SMC (Symmetrix Management Console)

ECC (EMC Control Center)


What are the Enginuity Operational Layes?

Symmetrix Based Application

Host Based Symmetrix Application

Independent Software vendor application

EMC Solutions Enabler API

Symmetrix Enginuity Operating Environment Functions

Symmetrix Hardware


What are the major components of System Bay and Storage Bay in DMX?

System Bay Components:

Either six or eight disk directors and up to 12 channel directors (Combined total = 16).

From four to eight global memory directors.

Up to eight power supplies, each of having a dedicated Battery Back Up(BBU)

1U service processor with KVM (keyboard, video screen and mouse) and dedicated UPS.

Three cooling fan assemblies (each containing 3 fans).


Storage Bay Components:

120 or 240 disk drives per storage bay

Each Drive Enclosure (DE) includes:

Two link control cards (LCC).

Redundant power supplies with BBUs to provide standby power.

The DMX-4 storage bay has 2N power zones with independent power cables, each zone capable of powering the fully configured storage bay.

The storage bay can be populated with various combinations of currently available DMX one-inch low-profile 4 Gb/s Fibre Channel disk drives available in:

73 GB, 146 GB, 300 GB, and 400 GB Fibre Channel drives

73 GB and 146 GB Flash drives

500 GB and 1 TB SATA II disk drives

Can you explain about Read Hit, Read Miss and Fast Write and Delayed Write?

Read Hit: In a read hit operation, the requested data resides in global memory. The channel director transfers the requested data through the channel interface to the host and updates the global memory directory. Since the data is in global memory, there are no mechanical delays due to seek and latency.

Read Miss: In a read miss operation, the requested data is not in global memory and must be retrieved from a disk device. While the channel director creates space in the global memory, the disk director reads the data from the disk device. The disk director stores the data in global memory and updates the directory table. The channel director then reconnects with the host and transfers the data. because the data is not in global memory, the symmetrix system must search for data on the disk and then transfer it to the channel adding seek and latency times to the operation.

Fast Write A fast write occurs when the percentage of modified data in global memory is less than the fast write threshold. On a host write command, the channel director places the incoming blocks directly into global memory. For fast write operations, the channel director stores the data in global memory and sends a “channel end” and “device end” to the host computer. The disk director then asynchronously destages the data from global memory to the disk device.

Delayed Fast Write: A delayed fast write occurs only when the fast write threshold has been exceeded. That is the percentage of global memory containing modified data is higher than the fast write threshold. If this situation occurs, the symmetrix system disconnects the channel directors from the channels. The disk director then de-stages the data to disk. When sufficient global memory space is available. The channel directors reconnect to their channels and process the fast I/O requires as a fast write. The symmectrix system continues to process read operations during delayed fast writes with sufficient global memory present, this type of global memory operation rarely occurs.


How do you calculate number of cylinders for 120 GB LUN?

Maximum device sizes by Enginuity version

Enginuity version:__________:MBs:_______:CYLs:______:GBs

Enginuity 5874:_____________:245760:____:262668:____:240

Enginuity 5773 and earlier:_:61425:_____:65520:_____:59


Since DMX-4 supports maximum of 60GB hyper size, we have to create two hypers and form a Meta devices as 120GB LUN.

To calculate cylinders for 60GB LUN use the below formula

Cylinders = 60GB/15 tracks* 8 sectors* 16 blocks * 512 bytes

Cylinders = 60000000000/15*8*16*512

Cylinders = 60000000000/983040

Cylinders = 61035 cyl

To calculate the number of cylinders (for pre-Symmetrix DMX), use either of the following: blocks ÷ 960 or (size in megabytes) x 2.1333

To calculate the number of cylinders (for Symmetrix DMX and Symmetrix V-Max arrays), use the following: 1 cylinder = 15 tracks; each track is 64 KB, 15 x 64 tracks = .937 MB for each cylinder

What is the maximum hyper size in DMX-4?

<p>Maximum Cylinders = 65520

Maximum Capacity = 59GB or 61425 MB

How many hypers can create in a Single disk in DMX4?

255 hypers per disk.


How many members can contain in one Meta?

1 Meta head + 255 members


How many LUN IDs available per FA port?

256 LUN IDs are available per FA port, 255 LUN IDs are usable out of 256.


What is Dynamic LUN addressing?

This feature will automatically selects and assigns the LUN IDs to the devices while device mapping to the port Instead of manually assigning address to the device while mapping


How do you add a new member to the existing Meta?

add dev XXXX to meta XXXX, protect_data=TRUE, bcv_meta_head=XXXX;

or for multiple ranges:

add dev XXX1:XXX6 to meta XXXX, protect_data=TRUE, bcv_meta_head=XXXX;


What is stripping and what is Concatenating?

Stripped Meta Devices:

Meta device addressing by striping divides each Meta member device into a series of stripes, addressing a stripe from each device before advancing to the next stripe on the first device. When writing to a striped volume, equal size stripes of data from each participating drive are written alternately to each member of the set.


Concatenated Meta Devices:

Concatenated devices are volume sets that are organized with the first byte of data at the beginning of the first device. Addressing continues to the end of the first device before any data on the next device is referenced. When 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 so on


What are the DMX-4 supported disk types, no. of disks and maximum capacity?

FC drives, iSCSI drives and Flash drives

15 drives per DAE

120 drivers per Cage

240 drives per Storage Bay

2400 drives per array If total of 10 storage bays connected

Maximum storage capacity is 1 PB.


Briefly explain the DMX-4 supported Device types?

Standard Devices: A Symmetrix device configured for normal Symmetrix operation under a desired protection method (such as RAID-1,RAID-S, and SRDF®).

Gatekeeper Devices: SCSI commands executed by SYMAPI are transferred to the Symmetrix array via a Symmetrix device that is designated as a Gatekeeper device. The gatekeeper allows you to retrieve configuration and status information from the Symmetrix array without interfering with normal device I/O operations.

Meta Devices: Allow individual devices to be concatenated to create larger devices.

BCV Devices: Specialized devices used to create a local copy of data contained in a standard Symmetrix device, which can be used for backup, restore, decision support, and application testing.

SRDF Devices (R1, R2 and R21) Devices configured as RDF1 or RDF2 to support SRDF operations.

R1 is source device for SRDF operations

R2 is target device for SRDF operations

R21 is used for multi hop SRDF operations

Virtual Devices: A host-accessible device containing track-level location information (pointers), which indicates where the copy session data is located in the physical storage. Device copies use virtual devices to support TimeFinder/Snap operations. Virtual devices consume minimal physical disk storage, as they store only the address pointers to the data stored on the source device or a pool of save devices.,

Save Devices: Special devices (not mapped to the host) that provide physical storage space for pre-update images or changed tracks during a virtual copy session of TimeFinder/Snap operations.

Device Masking (VCM)Devices: Symmetrix devices that have been masked for visibility to certain hosts. The device masking database (VCMDB) holds device masking records and typically resides on a 24 or 48 cylinder disk device..

DRV Devices: A non-user-addressable Symmetrix device used by the Symmetrix Optimizer to temporarily hold user data while reorganization of the devices is being executed. Typically, it is used by the Optimizer in logical volume swapping operations.


What is Vault drives and Hot Spare?

Vault Drivers: At the time of emergency shutdown of an Array, what ever the data in cache memory will be destaged/saved on temporary drives called vault drives

Hot Spare: At the time of physical drive failure hot spare drives will take place


What is Preview, Prepare and Commit while using Symconfigure command?

The preview argument verifies the syntax and correctness of each individual change defined, and then terminates the session without change execution.

The prepare argument performs the preview checks 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

The commit argument completes all stages and executes the changes in the specified Symmetrix array


What are the possible device service states and device status states?

Device Service States       : Normal, Failed and Degraded

Device Status States        : Ready, Not Ready and Write Disable.


How do you reserve the devices?

symconfigure -sid XXXX -f createdev.cmd -expire expiration date-owner myself -comment "this devices are reserved for SRDF activity" reserve


How do you create the Disk Groups

We can not create Disk Groups, It should be done by changing BIN file by CE.

We can rename the existing disk groups.

Example: symconfigure -sid 207 -cmd “set disk_group 4 disk_group_name = flash_dsks;” -v -nop commit


How do you check the free space by Disk group and Array as whole?

By Disk Group     :              Symdisk -sid XXXX list -by_diskgroup

Array as whole   :              Symconfigure -sid XXXX list -freespace


How do you check the total assigned devices to a particular Host?

Symmaskdb -sid XXXX list devs -wwn "host hba wwn"


How do you check the total allocated storage of a particular Host?

symmaskdb -sid XXXX list capacity -Host hostname


What is pre check list to assign storage to the host?

Verify the available free space in the symmetrix array

symconfigure -sid SymmID [-v | -freespace [-units cylinders | MB]] list

symdisk -sid "SymID" list -disk_group "GroupNumber"

Verify the Symmetrix status

Symconfigure -sid "SymID" verify

If any hung activities found abort

symconfigure -sid "SymID" abort


Explain step by step procedure to provide storage to the Host?

  1. Creating STD device
  2. Meta Device Creation
  3. Mapping
  4. Masking



Create a commandfile with the following entry to create hypers.

Create dev count=8, size=12394, emulation=FBA,  config=2-way-mir, disk_group=2;

Execute the command file using symconfigure command with preview, prepare and commit options.

Symconfigure -sid "SymID" -f Commandfile.cmd -v -noprompt commit

Verify the newly created devices

symdev -sid "SymID" list -noport

Create a commandfile with following entry to form metas and devices to the meta head.

Form  meta from dev 26CA, config=striped, stripe_size=1920;

add dev 26CB:26E4 to meta 26ca;


Execute the command file using symconfigure command with preview, prepare and commit options.

symconfigure -sid "SymID" -f Commandfile.txt -v -noprompt commit

Verify the newly created meta devices

symdev -sid "SymID" list -noport

Find the host connected Director and Port details

symcfg -sid 4282 list -connections

Find the available addresses on that port

symcfg -sid "SymID" list -address -available -dir 7d -p 0

Create a commandfile with the following entry to map the device to the FA port

map dev 26ca to dir 7d:0, lun=036;

Execute the commandfile using symconfigure with the preview, prepare and commit options.

Symconfigure -sid 4282 -f Commandfile.txt -v -noprompt commit

Mask the devices to the host HBA and refresh the sym configuration

symmaskdb -sid "SymID" -wwn 10000000c93f62cf -dir 7d -p 0 add devs 26ca -nop

Symmask -sid "SymiD" -refresh

Rescan the disks and refresh the powerpath or reboot the server to get the assigned devices at host-end


How do you check particular device geometry?

symdev -sid XXXX show dev 002C


How do you check the particular device is connected to which Host?

symmaskdb -sid XXXX list assignment -dev 002c


What are the steps for storage reclamation?


Write Disable


Dissolve meta

Deleting hypers


  1. Unmasking devices from the host

symmaskdb -sid 4282 -wwn 10000000c93f62cf -dir 7d -p 0 remove devs 26ca


  1. Refresh the Symmetrix Array

Symmask -sid 4282 -refresh


  1. Write Disable the devices before unmapping from the Director port

symdev -sid 4282 write_disable 26ca -sa 7d -p 0 -noprompt


  1. Create a cmd/txt file

Unmap dev 26ca from dir all:all;


  1. Perform preview operation using symconfigure command

Symconfigure -sid 4282 -f unmap.txt -v -nop preview


  1. Perform prepare operation using symconfigure command

Symconfigure -sid 4282 -f unmap.txt -v -nop prepare


  1. Perform Commit operation using symconfigure command

Symconfigure -sid 4282 -f unmap.txt -v -nop commit


  1. Verify that the device has been unmapped

Symdev -sid 4282 list -noport


  1. To Dissolve meta, create a cmd/txt file

Dissolve meta dev 26ca;


  1. Perform preview operation using symconfigure command

Symconfigure -sid 4282 -f dissolve.txt -v -nop preview


  1. Perform prepare operation using symconfigure command

Symconfigure -sid 4282 -f dissolve.txt -v -nop prepare


  1. Perform Commit operation using symconfigure command

Symconfigure -sid 4282 -f dissolve.txt -v -nop commit


  1. Verify that the meta has been Dissoved.

Symdev -sid 4282 list -noport


  1. To delete the hypers create a cmd/txt file.

Delete dev 26ca;


  1. Perform preview operation using symconfigure command

Symconfigure -sid 4282 -f dissolve.txt -v -nop preview


  1. Perform prepare operation using symconfigure command

Symconfigure -sid 4282 -f dissolve.txt -v -nop prepare


  1. Perform Commit operation using symconfigure command

Symconfigure -sid 4282 -f dissolve.txt -v -nop commit


  1. Verify that Hypers have been deleted.

Symdev -sid 4282 list -noport


How many mirror positions RAID-1 and RAID-5 will occupy?

RAID-1 occupies 2 mirror positions

RAID-5 occupies 2 mirror positions


How do you convert the concatenating meta device to stripped meta?

convert meta XXXX, config=striped, stripe_size=1920, protect_data=TRUE, bcv_meta_head=XXXX;


Host is unable to see the storage, how do you troubleshoot?

Check that the host is logged in to the Array

Check that the cable connectivity status by logging in to the host

Check that the HBA drivers are properly configured

Check the Zoning table by logging in to the switch

Check that the devices status in Array

Check the VCMDB for masking information, etc..


What is Thin Provisioning?

Thin provisioning is a method of optimizing the efficiency with which the available space is utilized in storage area networks. Thin provisioning operates by allocating disk space in a flexible manner among multiple users, based on the minimum space required by each user at any given time.


How do you create thin pools and thin devices?

Creating Thin Pools

Creating Data devs and added these Data devs to Thin Pools

Creating TDEVs and bind these TDEVs to Thin Pool

Assign TDEVs to host.


Explain step by step procedure to setup new host?

Let us assume cable connectivity is done properly

Install HBA drivers in host.

Install Power path if required.

Check that the HBA ports are showing online

Create zoning at switch end.

Check that this host is logged in to the Storage array

Create LUN/hypers in storage array

Form meta devices if required

Map the devices to the FA port.

Mask the devices to the host hba (wwn).

Refresh the Array to affect the changes.


How do you check the failed components in Symmetrix Array?

Symcfg -sid 150 list -env_data -service_state failed


How do you check the failed disks in the Symmetrix Array?

<p>Symdisk -sid XXXX list -failed


What is the purpose of Gate Keeper device?

Low-level I/O commands executed using SYMCLI are routed to the Symmetrix array by a Symmetrix storage device that is specified as a gatekeeper.


The gatekeeper device allows SYMCLI commands to retrieve configuration and status information from the Symmetrix array without interfering with normal Symmetrix operations.


The gatekeeper must be accessible from the host where the commands are being executed.


How many gate keeper devices are required per Array?

It depends on the Symmetrix management applications using in management servers,

As per EMC recommendations 6 gatekeepers are required per management host using symcli


How to list hosts and their EMC registered software, using Solutions Enabler?

Symcfg -sid XXXX list -applications


What is VCMDB and how do you take the backup?

The device masking database (VCMDB) holds device masking records and typically resides on a 24 or 48 cylinder disk device..

Symmaskdb -sid XXXX backup -f filename


How do you list the Hosts which are connected to particular director port?

Symmaskdb -sid XXXX list database -dir XX -p X


How do you check the number of storage bays connected to the system bay and number of disks in each storage bay?

Symcfg -sid XXXX list -env_data


How do check the devices which are not mapped and masked?

Symdev -sid 4282 list dev -noport


How do you check the devices which are mapped to FA but not masked to any host?

Symmaskdb -sid 123 list no_assignment -dir ALL -p ALL


How do you check the login hosts in the Symmetrix Array?

<p>Symmask -sid 4282 list logins


How to display and set the Symmetrix metrics?

Symcfg -sid XXXX -SA all list -v

Set Symmetrix MatricName=MatricValue


How do you check the configured environmental variables?

Symcli -def


Can windows, Linux, Solaris share the same FA in DMX?

Yes, if they share the same port flags


What are the Symmetrix External locks and how to check and release?

Symmetrix external locks are used by SYMAPI (locks 0 to 15) and also for applications assigned by EMC (>15) to lock access to the entire Symmetrix arrayduring critical operations


We can check the external locks by giving the below command

symcfg -sid XXXX list -lockn


We can check the external locks by giving the below command

symcfg release -sid <xxx> -lockn 15 -force


How to monitor performance of EMC Symmetrix?

Using Performance Monitoring feature in EMC Control Center

Using SYMSTAT symcli command


How do you check the cache activity of front-end directory?

symstat -sid 4282 -type cache -i 5 -c 4 -sa all


How do you check the I/O requests and throughput of selected disk?

Symstat -sid 4282 -type disk -i 5 -c 3 -disk 2a,C,5


What are the available performance types in SYMSTAT command?

REQUESTS: Reports I/O requests and throughput for selected devices, directors, or SRDF/A sessions. (This is the default type; if no type is specified REQUESTS is used.)

BACKEND: Reports back-end I/O requests and throughput for selected devices.

PORT: Reports performance statistics for a director port. ISCSI Report Gig-E network statistics.

CACHE: Reports cache activity for selected front-end or remote link directors, or SRDF/A sessions.

MEMIO: Reports cache memory to disk activity for selected devices. PATH Report R-Copy path information for nonincremental sessions. Symmetrix arrays that have all or some incremental sessions will report an error.

CYCLE: Report cycle summary information for SRDF-A sessions.

DISK: Reports back-end I/O requests and throughput for selected disks.

PREFETCH: Reports track prefetch disk activity for selected back-end directors only.DMSP Reports dynamic mirroring service policy (DMSP) statistics for the selected device(s).

RDF: Reports SRDF statistics from the perspective of RA groups, devices, or directors.


What is symmetrix optimizer and how it works?

Symmetrix Optimizer improves array performance by continuously monitoring access patterns and migrating devices (Symmetrix logical volumes) to achieve balance across the disks in the array

Step 1: Symmetrix Optimizer builds a database of device activity statistics on the Symmetrix back-end.

Step 2: Using the statistical data collected, configuration information, and the user-defined parameters, the Optimizer algorithm identifies busy and idle devicesand their locations on the physical drives. The algorithm tries to minimize average disk service time by balancing I/O activity across physical disks. Optimizer determines which disks require balancing by locating busy devices close to each other on the same disk, and/or by locating busy devices on faster disks or faster areas of the disks. Optimizer takes into account the speed of the disk, the disk geometry, and the actuator speed to determine faster disks.

Step 3: Once a solution for load balancing has been developed, the next phase is to carry out the Symmetrix device swaps. This is done using established TimeFinder technology, which maintains data protection and availability. we can specify whether swaps should occur in a completely automated fashion, or if the device swaps require user approval before the action is taken.

Step 4: Once a swap function completes, Symmetrix Optimizer continues data analysis for the next swap.


What is Symmetrix QoS and how it works?

Quality of Service (QoS) allows more flexibility in managing Symmetrix system’s performance. By increasing the response time for specific copy operations on selected devices, we can increase the overall performance of the other Symmetrix devices.

The QoS (Quality of Service) feature allows us to adjust the data transfer pace on specified devices, or devices in a device group, for certain operations.

The contention for cache access can be quality of service managed by the least recently used (LRU) ring partitions in the Symmetrix cache.

We can control the priority service time of devices and control cache partitions for different device groupings.


What is the purpose of Symmetrix Change Tracker?

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

Change Tracker data is often used to analyze and design TimeFinder and Symmetrix Remote Data Facility (SRDF) configurations.

Change Tracker (DeltaMark) session must be created using the symchg create command. The symchg mark command is then used to perform a timestamp and mark the selected area of disk storage occupied by a data object using a DeltaMark bitmap


What is Dynamic Cache Partitioning?

A QoS feature, dynamic cache partitioning allows the Administrator the means to dynamically control the cache area size, servicing a given device group I/O, by defining flexible partitions through cache memory.

Dynamic Cache Partitioning divides the cache memory into multiple partitions with unique names and their device path assignments.

Partition areas can be made static or dynamic in size. The dynamic partitioning provides flexibility to the amount of floating memory that can be allocated with a high and low watermark. This allows memory resources to be temporarily donated to other partitions when needed.

The symqos command allows you to create partitions for different device groupings in addition to the default partition that all devices belong to initially. Each partition will have a target cache percentage as well as a minimum and maximum percentage. In addition, you can donate unused cache to other partitions after a specified donation time.


What are the logs available at host-end and on symmetrix array?

Host-end logs are available in Symapilog folder

Event logs and Audit logs in symmetrix array


How do you monitor the real time events on symmetrix array with example?

To monitor real time 100 event records with 600 seconds interval  in the symmetrix array

Symevent -sid 4282 monitor -i 600 -c 100 -warn/-error/-fatal


How do you track the history of events on symmetrix array with example?

To list all events in symmetrix array

Symevent -sid 4282 list

To list specific period of time events in event logs

Symevent -sid 4282 list -v -start 9:00 -end 17:00


How do you check the audit logs on symmetrix array?

To show the details about audit log it self.

Symaudit -sid 4282 show

To list the audit log records of specific period of time.

Symaudit -sid 4282 list -v -start_time 7/11:9:00 -end_time 7/11:10:00

To monitor the real time audit logs 100 records with 30sec interval.

symaudit -sid 4282 monitor -i 30 -c 100


What is Symmetrix ACL?

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


Explain step by step to setup the access controls on symmetrix array?

Create Access Group:

(Create a command file with the following entries)

Create accgroup AccessGroupName;

(Execute the command file)

Symacl -sid 4282 commit -file commandfile


Add host access ID or user access ID to access group:

(Create a command file with the following entries)

Add host accid Id name Idname to accgroup GroupName;

Add user accid Id name Idname to accgroup GroupName;

(Execute the command file)

Symacl -sid 4282 -file "CommandFileName" commit


Create Access Pools:

(Create a command file with the following entries)

Create accpool AccessPoolName;

(Execute the command file)

Symacl -sid 4282 commit -file "commandfile"


Add devices to the access pool

(Create a command file with the following entries)

Add dev StartDevName:EndDevName to accpool AccessPoolName;

(Execute the command file)

Symacl -sid 4282 commit -file "commandfile"


Grant Rights to Access Groups:

(Create a command file with the following entries)

Grant access=Base/BCV/RDF to accgroup AccessGroupName to accpool AccessPoolName;

(Execute the command file)

Symacl -sid 4282 commit -file "commandfile"


How do you take the backup/restore of ACLs?
Symacl -sid 4282 backup -file "commandfile"
Symacl -sid 4282 commit -restore -f commandfile


What is Symmetrix User Authorization?
Set up or update the Symmetrix array user authorization information


Explain step by step procedure to setup user authorization on symmetrix array?
User-to-role mappings have to be created:
(Create a command file with the following entry (ex:rolemap.txt))
Assign user H:Hostusername to role Monitor;
Assign user D:Engusername to role Admin;
(Execute the above file)
Symauth -sid 4282 -f rolemap.txt commit.
(Roles: None, Monitor, Storage admin, admin, Auditor, SecurityAdmin)
Enable the user authorization:
Symauth -sid 4282 enable


How do you perform backup and restore user authorization information?
Symauth -sid 4282 backup -f backupfile.cmd commit
Symauth -sid 4282 restore -f backupfile.cmd commit


What is the purpose of bin file in SYMAPI database? 
It is a database file in the host which stores the symmetrix array’s configuration data. Can be used to get the configuration data offline.


How do you prepare the Storage Capacity planning reports by host wise?

  1. By using EMC Control Center
  2. By using symcli commands symcfg and symdisk

Symcfg -sid 4282 list -connections -capacity
Copy and past the output of the above command in excel file and format according to the requirement.
Symdisk -sid 4282 list -by_diskgroup
Copy and past the output of the above command in excel file and do the format according to the requirement.


By using what symcli command we can check the HBA details?
Syminq hba -fibre


What are the business continuity tools for symmetrix array?
Power path         - host end
TimeFinder          - local replication
SRDF                     - Remote Replication



Leave a Reply

Your email address will not be published. Required fields are marked *