Migrating volumes from one storage array to another using a mirror (plex)

Article:HOWTO36625  |  Created: 2010-12-08  |  Updated: 2014-01-02  |  Article URL http://www.symantec.com/docs/HOWTO36625
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Subject


BACKGROUND

 

  • The advantage of using this procedure versus a hardware solution is that using mirrors can be manipulated online and will not require a maintenance window from a Volume Manager perspective.  While this procedure can be run online, please understand the performance consideration of the mirroring process is relatively equivalent to a dd of the entire volume.  Additional online updates to the data may cause additional write operations to occur during the synchronization process of building the mirror and possibly increasing the time required.  Using the command 'vxtask -l list' will monitor Volume Manager administrative tasks and provide a real-time estimation of work time (see 'man vxtask' for details).

 

  • In the procedure below, <device> represents the OS appropriate device name disk access name (as reported in the 1st column of "vxdisk list"  (eg ... Solaris: c#t#d#, Linux: sdxx).

 

  • There are 2 methods of migrating SAN volumes.  Volume Manage commands can be used at the Unix command line.  Alternatively, the Veritas Operations Manager (VOM) has an add-on to perform enclosure migration.  The procedures presented below focus on the Volume Manager command method.  While it is beyond the scope of this document to go into detail about using VOM, the use  of Storage Provisioning/Enclosure Migration is presented below (VOM is a free graphical fault monitoring/administration tool available at http://go.symantec.com/vom ).

 

SUMMARY PROCEDURE

1)  Install new disks into the OS and configure into Volume Manager
2)  Initialize the new disks (vxdisksetup)
3)  Add the new disks to the diskgroup (vxdg adddisk)
4)  Create mirror plex (vxassist mirror)
5)  Disassociate the original plex (vxplex dis)
6)  Prior to removing the old disks/array
      a) Remove the original plex (vxedit rm)
      b) Remove the original disks from the disk group (vxdg rmdisk)
      c) Uninitialize the original disks (vxdiskunsetup)

 

DETAILED PROCEDURE

 

1)  Install new disks into the OS and configure into Volume Manager
 

A)  Use the appropriate OS/hardware procedures to install the drive(s)
B)  Use 'echo|format' to verify that the drives are recognized properly
C)  Use 'prtvtoc /dev/rdsk/<device>s2 (Solaris) on each device to verify the existence of a valid label (tags 14 and/or 15 should not exist).  Use fdisk -l in Linux, diskinfo in HP-UX (not applicable in AIX)
D)  Run 'vxdctl enable' to rescan all disks (I/O will not be interrupted)
E)  Verify that the new disks are seen in 'vxdisk list' with a status of "online invalid" or "error" ("error" in versions 3.5 and prior)

 

2)  Initialize the new disks (vxdisksetup)
 

A)  Command: 'vxdisksetup -i <device> format=<disk format>' on each of the new disks (where <format> is typically cdsdisk or sliced; use 'vxdisk list' to view current disk formats)
('vxdisk list' will now show each disk with a status of "online")

 

3)  Add the new disks to the diskgroup (vxdg adddisk)

 

A)  Command: 'vxdg -g <diskgroup> adddisk NewDisk<n>=<device>
(where <n> is a sequential # to designate each disk;"NewDisk<n>=" is optional)
B) 'vxdisk list' will now show each disk in the diskgroup (with a virtual name of NewDisk<n> if specified)

 

4)  Create mirror plex (vxassist mirror)
 

A)  Command: vxassist -g <diskgroup> mirror <volume> NewDisk1 NewDisk2 ...
(where "NewDisk<n>" is specified for each of the new disks specified separated by spaces)
(this can be monitored in another window with the command 'vxtask -l list')

 

5)  Disassociate the original plex (vxplex dis)
 

 

A)  Command: vxplex -g <diskgroup> dis <original plex>
(where <original plex> is the name of the plex in the output of "vxvol <volume>")
(output line starting with "pl")
(original plex: pl fwlogvol-01  fwlogvol     ENABLED  ACTIVE   281018880 CONCAT   -RW)
B)  Prior to step 6, this plex can be reattached to the volume if necessary using the command:
 "vxplex -g <diskgroup> att <volume> <plex>"

 

6)  Prior to removing the old disks/array

 

6A) Remove the original plex (vxedit rm)

- Command: 'vxedit -g <diskgroup> rm <original plex>'

6B) Remove the original disks from the disk group (vxdg rmdisk)

 

- Command: 'vxdg -g <diskgroup> rmdisk <device>' on each of the original drives

 

6C) Uninitialize the original disks (vxdiskunsetup)


-  Command: 'vxdiskunsetup -C <device>' on each of the original drives


The output of 'vxdisk list' should show the status of each disk on the old array as 'online invalid' before the old array is disconnected otherwise DMP will see this as a LUN failure and "cleanup" will be required.

 

If the OS /dev entries are present after removing the old array, 'vxdisk list' will still "see" the drive entries.

 

END OF COMMAND LINE PROCEDURES

 

Alternatively, the Storage Provisioning add-on in VOM can be used to migrate SAN enclosure based volumes.  The procedure below summarize this method.

1)  Access the Storage Provisioning add-on from the Solutions page.

 

 

2)  Choose the option Move volumes.

 

 

3)  Complete the template as appropriate.

 

 

 

VOM software, documentation and an overview is available at http://go.symantec.com/vom

 

 

 



Article URL http://www.symantec.com/docs/HOWTO36625


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