Wednesday, February 21, 2007

Off Host SnapShot

I was just revising my VxVM fundas, since it has been quite sometime before I have actually done it. More involved with backup off late.

Fast-Resync FlashSnap (Licensed Feature), Lets discuss 3rd mirror snapshot only as I have worked only on this feature.

Step 1 : Test bed starts with creation of a volume.

vxassist -g datadg make vol01 10g

Step 2 : Enable Fast Resync

vxsnap -g datadg prepare vol01

This also adds a DCO (Data Change Object), tracks changes and is

persistent across reboots.

Step 3 : Add mirror to the volume.

vxsnap -g datadg addmir datavol

This will add a mirror plex to the vol01, lets call it vol01-02

Step 4 : Now to create instant FULL sized snapshot.

vxsnap -g datadg make source=vol01/newvol=snapvol01/plex=vol01-02

Step 5 : Off host snap shot.

vxdg split datadg offdg snapvol01

Step 6 : Deport the DG

vxdg deport offdg

Step 7 : On the remote host, import the DG and mount. Use this

copy to perform backup operations, MIS e.t.c.

Step 8 : Deport the dg on the remote host.

vxdg deport offdg

Step 9 : Import it back on the original host.

vxdg import offdg

Step 10 : Join the DG's

vxdg join offdg datadg

Step 11 : Start the snapshot vol

vxvol -g datadg startall

Step 12 : Refresh the snapshot volume with the original volume.

vxsnap -g datadg refresh snapvol01 vol01


At 10:21 PM, Blogger Alan said...

Any info about how you would do a restore? Since a offhost back up may have a library attached to the backup server, would the restore process be a reverse step of what you described or would it be restorable directly from the library to the host itself assuming the host is also connected to the SAN tape library.

At 9:07 PM, Blogger BIJUCYBORG said...


If u wd like a restore then then

1. You can use the point in time copies u have already created.

2. Restore data onto fresh volumes from the tape library.


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