[Dovecot] Question about "slow" storage but fast cpus, plenty of ram and dovecot

Stan Hoeppner stan at hardwarefreak.com
Sun Dec 12 11:39:00 EET 2010

Patrick Westenberg put forth on 12/11/2010 5:12 AM:
> Stan Hoeppner schrieb:
>> So, either:
>> 2.  Move indexes to memory
> What steps have to be done and what will the configuration look like
> to have your indexes in memory?

Regarding Dovecot 1.2.x, for maildir, I believe it would be something
like this:

mail_location = maildir:~/Maildir:INDEX=MEMORY

The ":INDEX=MEMORY" disables writing the index files to disk, and as the
name implies, I believe, simply keeps indexes in memory.

The docs say:

"If you really want to, you can also disable the index files completely
by appending :INDEX=MEMORY."

My read of that is that indexing isn't disabled completely, merely
storing the indexes to disk is disables.  The indexes are still built
and maintained in memory.

Timo, is that correct?

Also, due to the potential size of the index files (mine alone are 276
MB on an 877 MB mbox), you'll need to do some additional research to see
if this is a possibility for you.  If using a ramdisk, 100 mail boxen
like mine would require ~ 27.6 GB or RAM just for the index files.  This
would not be logical to do or feasible given the amount of RAM required.
 I don't know if, or how much, storing them in RAM via :INDEX=MEMORY
consumes, as compared to using a ramdisk.  The memory consumption may be
less or it may be more.  Timo should be able to answer this, and give a
recommendation as to whether this is even a sane thing to do.


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