well ..you can use mountvol to mount/umount drives in Windows but if i were i would seriously consider purchasing Veritas storage foundation that includes clustering or migrate to Windows 2003 Enterprise edition and utilize built-in clustering functionality. Having two windows boxes in the same SG is just corruption waiting to happen. If you are going to go through the work of manually controlling your failover, might as well keep hosts in separate storage groups and manually move hosts in and out. My 5 cents

Thanks for your answer,
The purpose is to migrate from an old server to a new one,
meaning that the switching is going to be done once, then
I am going to remove the old server from the storage group.
Is mountvol sufficient to unmount the drives on the old server,
then mount it to the new (it's Windows 2003 server in fact) ?
Can I do the same with mouse click ?
Regards

i would stop your application or whatever it is you are migrating, flush everything to the drives using sync from http://technet.microsoft.com/en-us/sysinternals/bb897438.aspx. Then you can either use mountvol to umount the drive or just go to Disk Administrator and remove drive letter from drive(s). Take old server out, move new server in. You might have to reboot the new server but do make sure PowerPath picks up the LUNs.

You can have more than 1 host in a SG. In fact, in Flare 16 I think a warning appears that this is not recommended, but it does work. In higher / newer flare codes the warning is gone (or I don't even notice it anymore).

some comments:
you can`t add two servers in one SG, you must create separate SG for each server and add same luns to it.

That must be a bug then. I've been working with Clariions since almost 4 years now and have never seen that behavior.

On my storage with FLARE 24, if i add a second server in SG, first server kick off from SG.

Have you seen that behavoir before ? As long as I've been working with Navisphere (Flare 13 was my first) I was able to add more hosts to the same SG.

you have a big проблема ..problem ..cause in this case you can't create normal clustering configuration, well you could present same luns to different SG ..but that's not normal behavior. I would investigate that further.

Exactly, it works, the 2 servers see the same peripherals (library and lun).
Now, to avoid data corruption, I have to check the different steps to follow in
order to switch the lun from the old server from the new one . I have done it
with AIX (unmount FS, varyoffvg, then varyonvg), but never with windows, Any help ?
Regards
Consty