[Dovecot] index IO patterns

Hey all, we're in the process of checking out alternatives to our index storage. We're currently storing indexes on a NetApp Metrocluster which works fine, but is very expensive. We're planning a few different setups and doing some actual performance tests on them.

Does anyone know some of the IO patterns of the indexes? For instance:

• mostly random reads or linear reads/writes?
• average size of reads and writes?
• how many read/writes on average for a specific mailbox size?

Anyone do any measurements of this kind?

Alternatively, does anyone have any experience with other redundant storage options? Im thinking things like MooseFS, DRBD, etc?

regards,

Cor