We've been running dovecot director setup using MAILDIR++ spools on NFS served by 4 (aging) Netapp clustered filers and are considering modernizing our storage. There's nothing particularly wrong with the existing storage except the age, density and power consumption don't compare well when against new systems. Refreshing the Netapps is an option but they come at a substantial cost.
The last time we were looking one of the recommended hot DIY setups was Linux NFS backed by XFS on N mirrors but this predated the availability of stable ZFS in FreeBSD or Linux as well as products like FreeNAS. A FreeBSD NFS/ZFS filer on commodity hardware with zil/l2arc on a PCIe SSD seems like an attractive, affordable and easily scaled out solution which also would allow us to leverage compression at the filesystem layer.
Does anyone have any experience running ZFS spool storage? If so, how do you handle DR/HA for spool storage? Thoughts on how this might compare to using DRBD? Any pitfalls to watch out for or general pointers? Suggestions on pool configuration?
-K