I've not used this functionality without snapdrive, but there is always
a cmd way :-)
SnapDrive just automates things. In this case, it checks the metadata
of the volume on the SM destination and senses that it is indeed a
SnapMirror'ed volume. Then it breaks the SM relationship to make it
writeable and subsequently restores the LUN in question that you want to
connect to. Be warned - the SFSR functionality can take some
significant time... however, SnapDrive 4.0\ONTAP 7.1 significantly
reduces this operation by performing the block compare\filesystem writes
behind the scenes while the LUN is 'restored' via LUN clone\LUN split
(instead of the old SingleFileSnapRestore).
In your case, however... you'd have to trust that the LUN you wish to
connect to is consistent - snapdrive does do by using the last
consistent snapshot that it took (typically the '@snapmir@' one, if I
recall).
The difference between lun.rws and lun.lun is this: lun.lun is indeed
your LUN. Lun.rws is the 'temp space' allocated\associated with a
read\write LUN based off of a snapshot... there is no such thing (*ahem*
yet) as a read-only LUN in ONTAP. The .rws is just a placeholder for
any changes that you may make to the snapshot-version of the LUN you
mount to.
Be warned: creating a .rws file (done automatically via SnapDrive when
you connect to the LUN in a snapshot) will LOCK the snapshot you created
it from!! This is done to ensure that the mounted\active .rws LUN can
point to the data blocks needed to represent its contents (if you
deleted the snapshot, then you'd point to null data - not good). Any
subsequent snapshot taken _after_ mounting the .rws file will also lock
the previous snapshot. Be careful here!
Glenn
________________________________
From: owner-toasters(a)mathworks.com [mailto:owner-toasters@mathworks.com]
On Behalf Of Steven Mandrake
Sent: Friday, February 17, 2006 4:14 PM
To: toasters(a)mathworks.com
Subject: How to mount a snapmirror lun w/o snapdrive
Hi,
I have a lun that resides in a qtree and I am using volume level
snapmirroring to another filer. My primary filer has snapdrive for
connecting and creating luns.
My secondary filer does not have snapdrive. I want to mount my
snapmirrored luns to another host.
I understand there is a command line way of doing this. (lun -f). Has
anyone done it?
Also what is the difference between a lun.rws filer and a lun.lun file?
Thanks,
SM