We made a decision to not support VxVM mirror in a GCO environment because it breaks our ability to use SCSI-III based fencing. While you could make the mirror work, it is not a Symantec supported configuration. For dual cluster configs we would require some form of replication.
________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gene Henriksen Sent: Friday, December 28, 2007 5:49 AM To: Pavel A Tsvetkov; veritas-ha@mailman.eng.auburn.edu Subject: Re: [Veritas-ha] Is VxVM mirror supported in VCS GCO option? To mirror volumes you must be dealing with a relatively small distance, such as less than 80K. For these distances, why not use a single cluster called a "stretch" or "campus" cluster? In SF 5.0 there is the concept of "site awareness" so that VM is aware of the two sites and if a volume at the remote site becomes detached, then all volumes at the remote site are detached thereby maintaining consistency of the site. I have not heard of the limitation you mention, I do know that in a Replicated Data Cluster (VVR within a cluster), synchronous replication is required because unlike GCO there is nothing to prevent failover and we don't want the cluster to experience failovers and take over with old data automatically. With mirroring, it certainly would be possible. As in the case of replicating data we do not recommend automatic failover. Automatic failover could result in split brain destroying the data if the link between the two clusters were interrupted making it appear the primary cluster was down. A lot of configurations are possible, a lot will work, but they may not be supported. I am not sure who told you this, but I would ask for an explanation. One possible problem could be the loss of SAN between sites for hours followed by a failover to the remote site with old data with the VCS admin being unaware of the storage problem. I think the primary concern is split brain. With replication, you are working with two distinct data sets. If both sides become active due to a loss of connectivity, the data is not being corrupted, the two sites are just growing further apart. ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Pavel A Tsvetkov Sent: Friday, December 28, 2007 5:15 AM To: veritas-ha@mailman.eng.auburn.edu Subject: [Veritas-ha] Is VxVM mirror supported in VCS GCO option? Hello all! Just one interesting question about VCS GCO. I was told that VxVM mirror is not supported if using with Global Cluster Option. Only replicated volumes can be used ... Is it true? It seems strange to me... Why not? I think it is quite possible to failover mirrored VxVM volume between clusters... Or not??? Kind regards Pavel Tsvetkov
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