storing mail across several cyrus partitions

[Simon Matter]

>
>> Cyrus puts one folder on one partition. you can put subfolders on
>> other partitions, but you cant have two partitions connected with one
>> folder.
>> Cyrus has no way to decide where it would store the email on disk and
>> it would cost more time to merge these partitions in memory if a usere
>> access his mailfolder. This structure is used in all parts of cyrus.
>> To implement
>> something like this would be fundamental work like writing a new
>> mailserver.
>>
> Hm, does cyrus ever scan the content of filesystem (files,subfolders)?
> Or it uses direct access to filesytem objects like files and folders
> based on information from inner database?
>
> What is about  creating subpartitions like:
>
> /partition1/sub1/u/user/user1/*messages*
> /partition1/sub2/u/user/user1/*messages*
> /partition1/sub3/u/user/user1/*messages ?
>
> Creation of subpartitions seems to be fundamental too?
>
>>
>>> I would like to make extendable (by size) user mailboxes, but I don't
>>> want to move accounts over partitions when disk space becomes low,
>>> instead I want to attach new storages and store new mail there.
>>>
>>
>> There are more easy ways to do what you want.
>> 1. you can move user or subfolder to an other partition.
>>    In murdersetup you can do this even accros mailserver, without
>> downtime,
>>    if you run short in memory, cputime or bandwidth.
> Moving of accounts will cause downtime of the current account and will
> cause high loads on hardware when accounts are large...
> Also I want to be able to extend size of user's accounts without pain
> when my boss will ask to extend them x10 or x100 .....
>
>>
>> 2. you can put the partition on a filesystem/lvm-volume which supports
>>    resizing, so you can add a new dist to the volume and resize it.
>>
> May somebody recommend reliable/safe filesystem that support resizing?
> I'm afraid to use anything except ext3 in production enviroment...

We are using XFS on LVM for years now with cyrus-imapd and it has always
worked very well. Online expansion with this combination has saved us from
many hours of downtime over the years.

Simon