What stripe size for mail server?
Hi!
http://mail1.expro.pl/~porridge/dist.png shows the distribution of file
sizes on our mail server (actually just the partition holding maildirs).
The sample was 800000 files.
"-512" means zero-byte files.
"0" means the files whose sizes are greater than zero, but less than 512.
"512": greater than 512, but less than 1024
etc
The green line shows the distribution of messages in
Maildir/(new|cur|tmp). The red one also includes the number of other
files (mostly sqwebmail index and preferences files, .qmail, etc).
We probably need to optimize on reads, since currently there are 16
times more block reads than block writes on that partition. Given that,
what would be the best stripe size for (hardware) RAID 5 (currently 5
disks)? I read somewhere that large stripe sizes are good for small
random reads, but what is your experience? Or maybe RAID 5 is totally
unreasonable for such usage?
regards,
Marcin
--
Marcin Owsiany <porridge@debian.org> http://marcin.owsiany.pl/
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