storing mail across several cyrus partitions

[Michael Menge]

Quoting Artem Bokhan <artist at academ.org>:

>
>> 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?
>

Cyrus access the filesystem objects based on the informations on its  
databases.
But is able to reconstruct most of the informations with the  
reconstruct program.


> 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?
>

if you create a folder you can specify the partition this folder should be.
If you don't specify a partition it will be the same partition the parent
folder is on.


>>
>>> 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 .....
>

There are scripts out there which move the users/folders between  
partitions/servers in the night.

>>
>> 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 use XFS on ISCSI, till now we had no problems.

>> In both cases you are able to extend your space without changing cyrus
>> or downtime of the server
>>


--------------------------------------------------------------------------------
M.Menge                                 Tel.: (49) 7071/29-70316
Universitaet Tuebingen                  Fax.: (49) 7071/29-5912
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