Richard> Data ONTAP Release 8.1.2P1 7-Mode
Richard> Luns fibrechannel attached to IBM pSeries with AIX
Richard> Vols containing luns are snapmirrored to a DR site, and also Richard> snapvaulted to another filer.
Richard> I'd like to try out resizing a lun (FibreChannel attached to Richard> AIX) to increase it's size. Have never done this!
This is easy to do, esp on the netapp side. Just grow the volume, then grow the lun, then grow the destination volumes as well. Simple.
Richard> I know OnTap can resize a lun. What I'm not sure about is Richard> how that works with snapmirror and snapvault relationships. Richard> Snapmirror is at the volume level and shouldn't care. But Richard> snapvault in 7-mode is still at the object level - it works Richard> on the lun file. But then, SV should just copy the new Richard> blocks.
SM/SV just see a file, and the file just changed in size, so it will just send the changed blocks over.
Richard> So, I'm thinking lun expansion is no problem with SM and SV.
Correct.
Now you might have a problem with AIX seeing the change in the size of the LUN. You might need to unmount the device from whatever is using it before it will let is be re-sized.
Sometimes it's simpler to just make a new lun with the added size and then add it into the storage on the host (AIX) side so you can then grow the filesystem on top of it. But it's been years since I last touched AIX and I don't know the details well at all.
For my solaris hosts, I need to unmount the UFS filesystem before I can grow the device, then grow the filesystem. Then I can re-mount, which involves downtime.
If I had used a logical volume manager bewtween the device and the filesystem, it would be simpler and less disruptive to grow.
Cheers, John