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
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From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Steven Mandrake Sent: Friday, February 17, 2006 4:14 PM To: toasters@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