Andrew Morgan wrote: > Is there really a significant downside to performing backups on a hot > cyrus mailstore? Should I care if Suzie's INBOX was backed up at 3am > and Sally's INBOX was backed up at 4am? > > Vincent, on a slightly related note, what is your server and SAN > hardware? > I dunno, perhaps the Cyrus gurus could answer that better. I rather assumed I would want my meta information to match fairly closely the contents of the inboxes at that point in time. My belief was that if I had to a full restore after a disaster that I would have to spend substantial time doing reconstruct in order to get the databases to represent actual state. Thus having a point-in-time snapshot would be better for DR. Perhaps I'm wrong about that. Servers are fairly modest mostly Sun V245 a couple of T2000. Storage is a Belt and suspenders sort of hybrid/layered approach. We use a pair of cheapish Sun 2540 arrays. We multipath them through SAN switches. The arrays are configured with 2 5-disk RAID-5 LUNs and 2 hot spares. Then from the server view the 4 LUNS visible are pooled into a simple ZFS RAID-10. Since the mirror parts are composed of LUNS from each array, an entire array can go offline and it's mirror copy in the other array ensures uptime. I have had an entire array go down once due to controller issues and hey who HASN'T had an operator or someone working on cables pull the wrong power cords? It happens. We'd have to have 2 disk fail in a RAID-5 LUN and another disk in another LUN before I even furrow my brow. I've seen enough double-disk failures in RAID sets for one lifetime and certainly don't want to see one on mail store. Storage is cheap, downtime is not. Ordinary single-disk failures are handled through the array firmware swapping in a hot spare and barely rate notice except we have to eventually replace the dead disk. ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
