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@example.com. To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.