Recomendations for a Migration of a Cyrus mailStore with 70K users.
morgan at orst.edu
Thu Jun 17 13:01:35 EDT 2010
On Wed, 16 Jun 2010, Nestor A Diaz wrote:
> Hello Cyrus People.
> I have been always a proud user of the cyrus email system, currently my
> larger cyrus installation is about 70K users, which have been working
> fine, however i need to make some adjustems to improve the resposiviness
> of the mailstore.
> At the begining i use only a default mailstore, on a ext3 formatted
> filesystem over a raid 10 / LVM, it works fine, however when it reaches
> the 32768 directories, (a limitation of ext3) i have to create another
> partition, and then another one, so i have currently 3 partitions in total.
> Having defined some criteria in order to group every user into a
> partition i will like some recomendations, taking in mind the current
> cyrus server tools which i currently don't know what are their current
> capabilities, my plan is to forget using cyrus partitions, and instead
> using LVM partitions and the propper links to the physical partitions
> from the logical one.
> So i currently have:
> partition-default : 30K users
> partition-alt1: 20K users
> partition-alt2 : 20K users.
> and then i will like to have just one partition:
> partition-default ext4 formatted with links to physical partitions based
> on the first letter [a-z] of the user.
Have you seen the hashimapspool option:
If enabled, the partitions will also be hashed, in addition to the hashing done on con‐
figuration directories. This is recommended if one partition has a very bushy mailbox
This results in spool directories like
Unless you have more than 32k users with the same first letter in their
username, it should work well.
There is also a "fulldirhash" option, but I've never used it.
> I think LVM is a great advantage, and in some way aliviate the need for
> cyrus partitions, i it will lead me deal with the grow of a partition
> and data administration so easy without too much downtime.
> So, it means that accordingly to this stragegy which seems to be the
> most simple for me, what would be the best technical path to accomplish
> a good migration ? allowusermoves: yes option and renamemailbox is
> enoguth to do this task ? what if i want to do this online ? can i ? how
> ? is there any script that will help me do that ?
You can do online moves/renames.
> Any suggestions or migration histories are welcome !
> What about murder / perdition ? they make any sense in this configuration ?
Both Murder and Perdition would work to "scale out" to multiple servers.
They do add complexity though, so there is always a trade-off.
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