So with mdbox disk I/O usage increased compared to maildir+ramdisk indexes?
That is a "tricky" question to ask. It depends on usage, I think
the following:
- LDA delivery: load is a bit lower (on disk) in Maildir vs mdbox:
in both cases the message has to be written, indexes are updated, in
Maildir indexes are in ram, so lower "disk" load in this case
- POP3 access: the same as the previous post
- IMAP access: this is tricky. In mdbox a /"delete message"/
command only lowers the refcount, indexes are updated and in the night a
cron job runs doveadm purge. In Maildir, you really delete the message
when MUA/webmail /"compacts"/ the folder, and indexes are updated. I
think that mdbox has a /"delayed IO" /in this case, and has less load on
disk on "production hours".
Am I missing anything? The stats in the SAN after the change
maildir->mdbox do not help, we have zlib enabled in lda & imap with
mdbox, so our # of real IOPs is lower than Maildir (we did not have zlib
enabled)
Regards
Javier
