[Dovecot] SSD drives are really fast running Dovecot

[Ed W]

> Using XFS with delayed logging mount option (requires kernel 2.6.36 or later).
>
> XFS has natively used delayed allocation for quite some time, coalescing
> multiple pending writes before pushing them into the buffer cache.  This not
> only decreases physical IOPS, but it also decreases filesystem fragmentation by
> packing more files into each extent.  Decreased fragmentation means fewer disk
> seeks required per file read, which also decreases physical IOPS.  This also
> greatly reduces the wasted space typical of small file storage.  Works very well
> with maildir, but also with the other mail storage formats.

What happens if you pull out the wrong cable in the rack, kernel 
lockup/oops, power failure, hot swap disk pulled, or something else 
which causes an unexpected loss of a few seconds of written data?

Surely your IOPs are hard limited by the number of fsyncs (and size of 
any battery backed ram)?

Ed W