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Top 35 Emc Symmetrix Interview Questions

Q1. What Is Symmetrix Optimizer And How It Works?

Symmetrix Optimizer improves array overall performance by means of constantly monitoring access patterns and migrating devices (Symmetrix logical volumes) to acquire balance throughout the disks inside the array.

Step 1: Symmetrix Optimizer builds a database of device pastime information on the Symmetrix again-quit.

Step 2: Using the statistical facts accumulated, configuration data, and the person-described parameters, the Optimizer set of rules identifies busy and idle gadgets and their places at the physical drives. The algorithm attempts to limit common disk service time by way of balancing I/O pastime across bodily disks. Optimizer determines which disks require balancing with the aid of locating busy devices near every different on the identical disk, and/or by way of locating busy devices on faster disks or quicker regions of the disks. Optimizer takes under consideration the speed of the disk, the disk geometry, and the actuator velocity to determine faster disks.

Step three: Once an answer for load balancing has been advanced, the next segment is to carry out the Symmetrix device swaps. This is achieved using hooked up Time Finder era, which continues data protection and availability. We can specify whether swaps have to arise in a very automated style, or if the device swaps require person approval before the motion is taken.

Step four: Once a swap function completes, Symmetrix Optimizer keeps facts analysis for the next change.

Q2. How Do You Create The Disk Groups?

We cannot create Disk Groups; it need to be executed by way of changing BIN report by way of CE.

We can rename the prevailing disk groups.

Example: symconfigure -Sid 207 -cmd “set disk_group four disk_group_name = flash_dsks;” -v -nop dedicate.

Q3. How Do You Monitor The Real Time Events On Symmetrix Array With Example?

To display real time one hundred occasion information with six hundred seconds c language in the symmetrix array.

Symevent -sid 4282 reveal -i six hundred -c 100 -warn/-errors/-deadly.

Q4. What Is Symmetrix Acl?

To create access control listing on symmetrix array to put into effect host stage or person stage protection.

Q5. What Is Stripping And What Is Concatenating?

Stripped Meta Devices:

Meta device addressing by using striping divides every Meta member device into a chain of stripes, addressing a stripe from every tool earlier than advancing to the next stripe on the primary device. When writing to a striped volume, identical length stripes of information from each collaborating power are written alternately to every member of the set.

Concatenated Meta Devices:

Concatenated gadgets are extent units that are organized with the first byte of information at the start of the first device. Addressing keeps to the quit of the primary device earlier than any statistics on the next device is referenced. When writing to a concatenated tool, the primary meta device member receives all of the information until it is full, after which statistics is directed to the subsequent member and so forth.

Q6. What Is Dynamic Lun Addressing?

This function will robotically selects and assigns the LUN IDs to the gadgets at the same time as device mapping to the port Instead of manually assigning cope with to the tool while mapping.

Q7. What Is The Purpose Of Gate Keeper Device?

Low-level I/O instructions finished the use of SYMCLI are routed to the Symmetrix array by way of a Symmetrix garage device this is precise as a gatekeeper.

The gatekeeper tool lets in SYMCLI instructions to retrieve configuration and standing statistics from the Symmetrix array without interfering with ordinary Symmetrix operations.

The gatekeeper must be available from the host where the commands are being achieved.

Q8. What Is The Purpose Of Bin File In Symapi Database?

It is a database file inside the host which shops the symmetrix array configuration records.

Can be used to get the configuration facts offline.

Q9. What Is The Maximum Hyper Size In Dmx-4?

Maximum Cylinders = 65520

Maximum Capacity = 59GB or 61425 MB

Q10. How Do You Create Thin Pools And Thin Devices?

Creating Thin Pools.

Creating Data devs and delivered these Data devs to Thin Pools.

Creating DEVs and bind these DEVs to Thin Pool.

Assign DEVs to host.

Q11. What Are Preview, Prepare And Commit While Using Symconfigure Command?

The preview argument verifies the syntax and correctness of each man or woman alternate defined, and then terminates the consultation with out change execution.

The prepare argument plays the preview tests and also verifies the appropriateness of the ensuing configuration definition in opposition to the modern-day state of the Symmetrix array; the argument then terminates the session without trade execution.

The commit argument completes all tiers and executes the changes within the designated Symmetrix array.

Q12. How Do You Prepare The Storage Capacity Planning Reports By Host Wise?

By means of the use of EMC Control Center

by using symcli commands Symcfg and Symdisk

Symcfg -Sid 4282 listing -connections -capability

Copy and paste the output of the above command in excel report and format in keeping with the requirement.

Q13. What Is Symmetrix User Authorization?

Set up or replace the Symmetrix array person authorization statistics.

Q14. What Is The Purpose Of Symmetrix Change Tracker?

To degree adjustments to records on a Symmetrix volume or group of volumes.

Change Tracker statistics is often used to analyze and design Time Finder and Symmetrix Remote Data Facility (SRDF) configurations.

Change Tracker (Delta Mark) consultation ought to be created the use of the symcli create command. The symchg mark command is then used to perform a timestamp and mark the selected area of disk garage occupied by a statistics object using a Delta Mark bitmap.

Q15. How Do You Check The Audit Logs On Symmetrix Array?

To show the information about audit log itself.

Symaudit -Sid 4282 display.

To list the audit log facts of specific time period.

Symaudit -Sid 4282 listing -v -start time 7/eleven:9:00 -quit time 7/11:10:00

To reveal the real time audit logs one hundred information with 30sec interval.

Symaudit -Sid 4282 monitor -i 30 -c @

Q16. How Do You Check The Free Space By Disk Group And Array As Whole?

By Disk Group: Symdisk -Sid XXXX listing -by_diskgroup.

Array as whole: Symconfigure -Sid XXXX list –freespace.

Q17. Explain Step By Step Procedure To Setup User Authorization On Symmetrix Array?

User-to-function mappings have to be created:

(Create a command document with the following access (ex: rolemap.Txt))

Assign user H: Host username to role Monitor;

Assign consumer D: Eng username to role Admin;

(Execute the above file)

Symauth -sid 4282 -f rolemap.Txt dedicate.

(Roles: None, Monitor, Storage admin, admin, Auditor, SecurityAdmin)

Enable the user authorization:

Symauth -Sid 4282 enable.

Q18. How Do You Take The Backup/restore Of Acls?

Symacl -sid 4282 backup -report "command document"

Symacl -sid 4282 commit -repair -f command document

Q19. Explain Step By Step Procedure To Setup New Host?

Let us anticipate cable connectivity is accomplished well.

Install HBA drivers in host.

Install Power direction if required.

Check that the HBA ports are showing online.

Create zoning at switch give up.

Check that this host is logged in to the Storage array

Create LUN/hyper in storage array.

Form Meta devices if required.

Map the devices to the FA port.

Mask the gadgets to the host hba (wwn).

Refresh the Array to have an effect on the changes.

Q20. What Is Vcmdb And How Do You Take The Backup?

The tool protecting database (VCMDB) holds device masking facts and usually resides on a 24 or 48 cylinder disk device.

Symmaskdb -Sid XXXX backup -f filename.

Q21. What Are The Business Continuity Tools For Symmetrix Array?

Power direction - host stop

Time Finder - local replication

SRDF - Remote Replication

Q22. How Many Lun Ids Available Per Fa Port?

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

Q23. What Is Vault Drives And Hot Spare?

Vault Drivers: At the time of emergency shutdown of an Array, whatever the information in cache memory can be destaged/stored on brief drives called vault drives.

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

Q24. How To Display And Set The Symmetrix Metrics?

Symcfg -Sid XXXX -SA all listing -v

Set Symmetrix MatricName=MatricValue

Q25. How Many Gate Keeper Devices Are Required Per Array?

It depends at the Symmetrix management applications using in control servers.

As in step with EMC suggestions 6 gatekeepers are required according to management host using symcli.

Q26. What Are The Symmetrix External Locks And How To Check And Release?

Symmetrix external locks are utilized by SYMAPI (locks zero to 15) and also for applications assigned by means of EMC (>15) to fasten get admission to to the entire Symmetrix array during important operations.

We can take a look at the external locks through giving the below command

Symcfg -Sid XXXX list -lockn

We can take a look at the outside locks through giving the underneath command

Symcfg release -Sid -lockn 15 -force

Q27. What Is Symmetrix Qos And How It Works?

Quality of Service (QoS) permits more flexibility in handling Symmetrix device’s performance. By growing the reaction time for unique reproduction operations on decided on devices, we are able to increase the general overall performance of the alternative Symmetrix gadgets.

The QoS (Quality of Service) feature lets in us to adjust the facts trfer tempo on special gadgets, or gadgets in a tool organization, for sure operations.

The contention for cache get right of entry to may be first-class of carrier controlled by the least these days used (LRU) ring walls within the Symmetrix cache.

We can control the concern provider time of gadgets and control cache partitions for unique device groupings.

Q28. How To Monitor Performance Of Emc Symmetrix?

Using Performance Monitoring characteristic in EMC Control Center.

Using SYMSTAT symcli command.

Q29. What Is Thin Provisioning?

Thin provisioning is a method of optimizing the efficiency with which the available space is utilized in garage place networks. Thin provisioning operates by allocating disk space in a bendy way amongst more than one customers, based at the minimum area required by way of every person at any given time.

Q30. What Are The Available Performance Types In Symstat Command?

REQUESTS: Reports I/O requests and throughput for selected gadgets, directors, or SRDF/a session. (This is the default type; if no type is distinctive REQUESTS is used.)

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

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

CACHE: Reports cache hobby for selected front-cease or faraway hyperlink administrators, or SRDF/A classes.

MEMIO: Reports cache memory to disk pastime for decided on gadgets. PATH Report R-Copy route records for no incremental sessions. Symmetrix arrays which have all or a few incremental sessions will document an errors.

CYCLE: Report cycle summary statistics for SRDF-A classes.

DISK: Reports returned-cease I/O requests and throughput for selected disks.

PREFETCH: Reports music prefetch disk interest for decided on again-stop director’s only.DMSP Reports dynamic mirroring provider policy (DMSP) records for the chosen tool(s).

RDF: Reports SRDF records from the perspective of RA corporations, gadgets, or directors.

Q31. What Is Dynamic Cache Partitioning?

A QoS feature, dynamic cache partitioning lets in the Administrator the me to dynamically manipulate the cache region length, servicing a given device group I/O, by means of defining flexible partitions via cache memory.

Dynamic Cache Partitioning divides the cache reminiscence into multiple walls with specific names and their device course assignments.

Partition areas may be made static or dynamic in length. The dynamic partitioning provides flexibility to the amount of floating memory that can be allocated with a excessive and coffee watermark. This permits reminiscence assets to be temporarily donated to other walls while wished.

The symqos command permits you to create partitions for specific tool groupings further to the default partition that each one devices belong to to start with. Each partition could have a goal cache percentage as properly at the least and maximum percentage. In addition, you could donate unused cache to other walls after a exact donation time.

Q32. What Are The Logs Available At Host-give up And On Symmetrix Array?

Host-quit logs are to be had in Symapi log folder

Event logs and Audit logs in symmetrix array

Q33. How Do You Perform Backup And Restore User Authorization Information?

Symauth -Sid 4282 backup -f backupfile.Cmd commits

Symauth -Sid 4282 repair -f backupfile.Cmd devote

Q34. 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 time frame occasions in event logs

Symevent -Sid 4282 listing -vs -start nine:00 -end 17:00

Q35. Host Is Unable To See The Storage, How Do You Troubleshoot?