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SnapView on HP9000
I have a site with HP9000 Itanium servers running HP-UX 11iV2 connected to a CX700 on release 24.
The HP systems have dual hba's and use PVlinks for failover - since PowerPath was not available for 11iV2 when the servers were implemented (although of course it is now). Both snapclones & snapshots are taken of secondary MirrorView luns on the CX700, and these are then used for backups.
The problem is that while the passive paths to the respective luns appear to present the same to HP-UX whether they are clones or snapshots, only those of the clone luns are able to be added as alternate paths to a volume group via the 'vgextend' command. Attempting to add the snapshot passive paths, results in errors like: "vgextend: Physical Volume "/dev/dsk/c33t1d6" contains no LVM information". This means that if the snapshot source lun is trespassed HP-UX will take the snapshot volume offline.
Has anyone else encountered this limitation, and if so how did you get around it? While I suspect that EMC's response would be to just install PowerPath, it seems that there is a subtle difference (bug??) in the way that SnapView presents clone and snapshot luns to a host, or at least an HP one.
The HP systems have dual hba's and use PVlinks for failover - since PowerPath was not available for 11iV2 when the servers were implemented (although of course it is now). Both snapclones & snapshots are taken of secondary MirrorView luns on the CX700, and these are then used for backups.
The problem is that while the passive paths to the respective luns appear to present the same to HP-UX whether they are clones or snapshots, only those of the clone luns are able to be added as alternate paths to a volume group via the 'vgextend' command. Attempting to add the snapshot passive paths, results in errors like: "vgextend: Physical Volume "/dev/dsk/c33t1d6" contains no LVM information". This means that if the snapshot source lun is trespassed HP-UX will take the snapshot volume offline.
Has anyone else encountered this limitation, and if so how did you get around it? While I suspect that EMC's response would be to just install PowerPath, it seems that there is a subtle difference (bug??) in the way that SnapView presents clone and snapshot luns to a host, or at least an HP one.
- what if you vgimport vgimport -v /dev/vg01 /dev/dsk/c1d0s2 /dev/dsk/c3d0s2
and then trespass source lun and then vgextend the alternate path? I guess you would need to do it everytime you add volume to production.
Message was edited by:
dynamox - If you are mounting the clone VG on the same host as the source VG it is critical that you run vgchgid command against the clone physical device files to avoid running into conflicts.
This is true regardless of the replication technology and is the only way to ensure that you do not run into a potential data corruption issue on your HP-UX server.
d2dowling
30 Posts
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Posted July 24th, 2007 18:00