Thanks again for your help, Mike! Now, I've got it working completely independently from iSCSI with just the "device mapper".
1. pause the VM 2. "dmsetup suspend" the storage 3. bring up new iSCSI target on storage cluster and login to it 4. "dmsetup load" stuff to bind the new iSCSI target 5. "dmsetup resume" the storage 6. resume the VM 7. clean up old target stuff Cheers, Sebastian On 05/08/11 08:55, Sebastian Riemer wrote: > Thanks, Mike for the valuable information. I will try both: dm-multipath > and the redirection. > > > On 05/08/11 01:03, Mike Christie wrote: > >> On 08/02/2011 06:19 AM, Sebastian Riemer wrote: >> >> >>> This is the sequence: >>> 1. pause the VM >>> 2. unlink replication to new location, new target becomes primary >>> 3. logout from old iSCSI target >>> 4. login to new iSCSI target, BUT with the same block device as it is >>> held open >>> >>> >> The problem with 3 and 4 and using the iscsi disk directly and not using >> something like iscsi login redirect, is that on logout the device >> (/dev/sdXYZ) is going to be destroyed, so if something was referencing >> it they are basically screwed. All further access with result in IO errors. >> >> When you do #4 and login you get a new /dev/sdXYZ and so your app has to >> open that and use it. >> >> If your setup can just use dm-multipath then you can just multipath over >> iscsi. When you logout it would just destroy what the multipath device >> sees as a path. Then when you login, it will add it as a new path. You >> can then resume the VM and it would never know that the paths under the >> multipath device got swithced around. >> >> >> >>> Does iSCSI target redirection work without stopping VMs? >>> >>> >> Yeah, it should. But we can only redirect to another portal. If you are >> looking at the open iscsi userspace source code see >> usr/login.c:iscsi_update_address and initiator.c's >> __check_iscsi_status_class's ISCSI_LOGIN_STATUS_TGT_MOVED_PERM handling. >> >> So the target name would have to be the same but the portal info could >> be different. >> >> -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.
