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Last time I showed you how to add a new drive to make a new disk group. Well, what if you already have a disk group, with just one drive on it and you want to mirror that data across another drive? The process is easy and here’s how:

Let’s start off with a simple disk group:

# vxprint
Disk group: tempdg-tmp

TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0
dg tempdg-tmp tempdg-tmp – – – – – -

dm tempdg-tmp02 emcpower1s2 – 733975296 – – – -

v templv-tmp fsgen ENABLED 733975296 – ACTIVE – -
pl templv-tmp-02 templv-tmp ENABLED 733975296 – ACTIVE – -
sd tempdg-tmp02-01 templv-tmp-02 ENABLED 733975296 0 – – -

This shows the disk group’s name is tempdg-tmp, the original disk in the group is called tempdg-tmp02, the logical volume is called templv-tmp, which is made up of one plex called templv-tmp-02, which has one subdisk called tempdg-tmp02-01.

So, let’s add an additional disk tempdg-tmp01 and use it to mirror the data on tempdg-tmp02. If we look first at how the device is setup for the original drive we see that it is using cdsdisk format:

# vxdisk -o alldgs list
DEVICE TYPE DISK GROUP STATUS
emcpower1s2 auto:cdsdisk tempdg-tmp02 tempdg-tmp online

So let’s make our new device cdsdisk formatted as well:

# vxdisk -o alldgs list
DEVICE TYPE DISK GROUP STATUS
emcpower6s2 auto:none – – online invalid

# /etc/vx/bin/vxdisksetup -i emcpower6 format=cdsdisk

# vxdisk -o alldgs list
DEVICE TYPE DISK GROUP STATUS
emcpower6s2 auto:cdsdisk – – online

Now to add the new disk to the disk group. Note that since the original drive was called 02, the one we are adding is 01:

# vxdg -g tempdg-tmp adddisk tempdg-tmp01=emcpower6

Now we can see the new drive in the disk group (and that it isn’t currently doing anything):

# vxprint
Disk group: tempdg-tmp

TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0
dg tempdg-tmp tempdg-tmp – – – – – -

dm tempdg-tmp01 emcpower6s2 – 733975296 – – – -
dm tempdg-tmp02 emcpower1s2 – 733975296 – – – -

v templv-tmp fsgen ENABLED 733975296 – ACTIVE – -
pl templv-tmp-02 templv-tmp ENABLED 733975296 – ACTIVE – -
sd tempdg-tmp02-01 templv-tmp-02 ENABLED 733975296 0 – – -

So let’s tell the disk group to set tempdg-tmp01 up as a mirror of tempdg-tmp02:

# vxassist -g tempdg-tmp mirror templv-tmp tempdg-tmp01 &

I ran it in the background because it can take a long time depending on how big it is (about 2 hours for 350 GB). To watch the mirroring process, use vxtask. (You can also use vxprint to see what it is doing.)

# vxtask list
TASKID PTID TYPE/STATE PCT PROGRESS
177 ATCOPY/R 04.89% 0/733975296/35921920 PLXATT templv-tmp templv-tmp-01 tempdg-tmp

Once it completes, you will see your new drive setup as a mirror:

# vxprint
Disk group: tempdg-tmp

TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0
dg tempdg-tmp tempdg-tmp – – – – – -

dm tempdg-tmp01 emcpower6s2 – 733975296 – – – -
dm tempdg-tmp02 emcpower1s2 – 733975296 – – – -

v templv-tmp fsgen ENABLED 733975296 – ACTIVE – -
pl templv-tmp-02 templv-tmp ENABLED 733975296 – ACTIVE – -
sd tempdg-tmp02-01 templv-tmp-02 ENABLED 733975296 0 – – -
pl templv-tmp-01 templv-tmp ENABLED 733975296 – ACTIVE – -
sd tempdg-tmp01-01 templv-tmp-01 ENABLED 733975296 0 – – -

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This entry was posted on Monday, May 25th, 2009 @ 9:25 am on the category Technical.You can follow any responses to this entry through the RSS 2.0 You can leave a response, or trackback from your own site.