DMX-4 Interview Preparation

DMX-4 Step by Step Procedure for storage provisioning & Reclamation in DMX-4

Storage Provisioning ­­­

 Creating STD device

 Forming Meta Device

 Mapping

 Masking

Storage Reclamation

 Unmasking

 Write Disable

 Un-mapping

 Dissolve meta

 Deleting hypers

Q: Host is unable to see the storage, what may be the problem?

1. Zoning/masking not done

2. Correct Flags not set at the FA level

3. HBA does not have correct driver or firmware

4. Multipathing issues

5. Lun offset might not have been done in case of old DMX.

Q: How doyou check the failed disks in theSymmetrixArray?

symdisk list-failed

or

symdev list-servcie_state failed and thenrun a symdev showon that device

Q: How doyou check the freespacebyDiskgroupand Arrayas whole?

symconfigurelist-freespaceor moreaccurate is symdisk list-dskgrp_summary

­

Q: Symmetrix Architecture

·        Front End Director

·        Cache

·        Back End Director

·        Disk Devices

·        Interconnect

VCM Database: The Symmetrix Volume Configuration Management (VCM) database stores access configurations that are usedto grant host access to logical devices in a Symmetrix storage array.

Zone Limits:

·       64 zone sets (max)

·       2000 zones (max)

·       1024 zones per zone set (max)

·        deafult should all ways be disabled (causes all port to see each other creating ghosts in a FA's login table)

Hard and Soft zoning: hard zoning is using the physical connection to block zone access and

soft zoning uses software to block access to a zone i.e software within a switch.

LUN Masking: There is other zoning which is called LUN masking, this is normally handled by the SAN array and only allows specific hosts to see specific devices within the array.

Q: 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

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:Host\username to role Monitor;
Assign user D:Eng\username 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

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.
Or
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.