Reducing ZFS blocksize to improve Cyrus write performance ?

[Pascal Gienger]

Am 09.08.10 17:33, schrieb Pascal Gienger:

> A smaller record size is a good option if you notice an i/o bottleneck
> on your fiberchannel/iSCSI/SAS link. It won't bring you a performance
> gain in random i/o. There is a small exception: Database systems writing
> always the same fixed blocksize. For MySQL some people advise 32k.

Just another note:
For us, gzip compression had a performance plus, reducing i/o bandwidth 
much better than a smaller recordsize (gzip compression for the 
mailstore, NOT (!) for the meta partition containing the cyrus.* files!).

Just for your info as a reference, we're running happy with this:

-bash-3.00$ zfs get all mail/imap
NAME       PROPERTY              VALUE                  SOURCE
mail/imap  type                  filesystem             -
mail/imap  creation              Mon Aug 13 13:19 2007  -
mail/imap  used                  1.58T                  -
mail/imap  available             4.96T                  -
mail/imap  referenced            1.51T                  -
mail/imap  compressratio         1.61x                  -
mail/imap  mounted               yes                    -
mail/imap  quota                 none                   default
mail/imap  reservation           none                   default
mail/imap  recordsize            128K                   local
mail/imap  mountpoint            /mail/imap             default
mail/imap  sharenfs              off                    default
mail/imap  checksum              on                     default
mail/imap  compression           gzip                   local
mail/imap  atime                 off                    local
mail/imap  devices               off                    local
mail/imap  exec                  off                    local
mail/imap  setuid                off                    local
mail/imap  readonly              off                    default
mail/imap  zoned                 off                    default
mail/imap  snapdir               hidden                 default
mail/imap  aclmode               groupmask              default
mail/imap  aclinherit            restricted             default
mail/imap  canmount              on                     default
mail/imap  shareiscsi            off                    default
mail/imap  xattr                 on                     default
mail/imap  copies                1                      default
mail/imap  version               1                      -
mail/imap  utf8only              off                    -
mail/imap  normalization         none                   -
mail/imap  casesensitivity       sensitive              -
mail/imap  vscan                 off                    default
mail/imap  nbmand                off                    default
mail/imap  sharesmb              off                    default
mail/imap  refquota              none                   default
mail/imap  refreservation        none                   default
mail/imap  primarycache          all                    default
mail/imap  secondarycache        all                    default
-bash-3.00$