Cyrus mailboxes and OpenAFS

[Derrick J Brashear]

On Mon, 26 Jul 2004, Stuart Merrill wrote:

> I'm attempting to configure a network of servers with SuSE Enterprise 8.0
> looking after a RAID array with tape backup and SuSE OpeneXchange 4.1 (which
> I believe is a version of Cyrus) on a different server managing
> e-mail/groupware.
>
> I want to put the mailboxes (in fact any volatile data) on the RAID array,
> but have been told by many that there are locking issues - this is confirmed
> with your
> "Cyrus IMAP Server Installation FAQ" section headed "NFS (don't)".

(I assume then that the raid array cannot simply be attached and made 
"local disk" to the machine you wish to install the Cyrus server on?)

> I have been directed towards OpenAFS (another of your projects), have
> obtained the source from SuSE and am in the process of compiling and
> installing it (not without difficulty, mind you).
>
> Before I venture any further, does OpenAFS overcome all the issues that NFS
> fails to cover, or should I be re-thinking my entire approach to the
> configuration of the servers?

Using OpenAFS as a backend for Cyrus has its own perils.
1) you must either ACL the AFS space so the Cyrus server's IP address can 
write or run the Cyrus server with AFS credentials.
2) if you want concurrent writing from multiple machines, it's probably 
still not what you want

but the most important point:
3) AFS has a limit in the number of files you can put in a directory.
For the sake of argument (given the filenames you'll have for messages)
let's just say it will be 65535. There are people who keep more messages 
in a mailbox than that.

> I see from your "archive.info-cyrus - 12230" (a few years old!) that then
> the thread advised to steer clear of AFS as "I/O throughput is limited".

Not all of the issues have been fixed there, no.
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