[OpenIndiana-discuss] ZFS High-Availability and Sync Replication

[Edward Ned Harvey (openindiana)]

> From: Doug Hughes [mailto:doug at will.to]
> 
> Well, to me, the most obvious is use another box with ZFS to mirror the
> ISCSI devices on ZFS. I'm in the process of doing this myself with some
> stuff. 2 head nodes and 2 storage nodes. The storage nodes are targets
> and the head nodes are initators. You get performance and reliability,
> and failover between head nodes is relatively easy with zpool import.

This is precisely the thing I did with poor results, except that I didn't have 4 nodes - I had only 2.  So each node was both an initiator and a target.  I made the initiator service dependent on the target service (so the initiator would go down first and come up second).  I made zpool import of the iscsi pool dependent on the initiator being up, and I made vbox dependent on the iscsi zpool mounter.

(see simplesmf, http://code.google.com/p/simplesmf/ for the zpool dependent on iscsi initiator)

My word of advice, until such time (which may never come) that I might know more...  Never, ever let the iscsi targets go down unless the initiators are both down first.