Hello list, there has been some discusstions about how to replicate ZFS. The only way to do it synchronously (at least on OpenSolaris) is Sun AVS (SNDR).
The "typical" Sun AVS setup looks like this: - Backend Disks are replicated with AVS - ZPOOL is created on those disks In case you ned to switch, you disable the avs and import the pool in the standby side. This involves importing the pool, created the dev nodes which all takes time etc. Also the performance of the pool is degraded, because by the required use of consistency groups, a lot of parallellism is elimited (or isn't it ?). While this works for ZFS and ZVOL, for bigger setups, the failover tim may be an issue (for iSCSI you have to be below 2 minutes to avoid tweaks I believe). So I though about why not do it the other way around, replicating ZVOLS. This has several advantages: 1) The target pool is imported 2) On failover, only the export of the zvol as iSCSI needs to be done 3) The target zvol cache may be hot (at least for writes) 4) The write order sonsistency needs to be maintained for one zvol only, which allows for parlallism below the zvol (at the disk level) 5) Pool integrity would not be possibly damaged if replication direction fails, we can go back to tthe latest local pool snapshots. It also has disadvantages: 1) Probably more replication pairs (some hundred zvol environments) 2) Snapshots are not replicated 3) not suitable for ZFS filesystems (only zvol) Has anyone setup sommething like this ? Ar there (internal) OpenSolaris limitations not allowing for this setup ? Any thoughts ? p.s. maybe this is better @zfs-discuss ? Regards, Robert -- This message posted from opensolaris.org _______________________________________________ storage-discuss mailing list storage-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/storage-discuss
