Anyone using Linux LVM with cyrus?

[Simon Matter]

Hans Wilmer schrieb:
> 
> On Wed, Feb 05, 2003 at 04:36:03PM -0400, Patrick Boutilier wrote:
> 
> > We are using LVM to give the ability to add disk space and expand our
> > reiserfs when necessary.
> 
> Is it possible to add disc space with ext3fs and LVM, too?
> 
> > We are using LVM on top of hardware RAID 5 so as long as 2 disks don't
> > fail at once we should be OK.
> 
> Hm, sounds nice :)
> 
> To be more specific, what I've in mind is a setup like that, for
> 60--100 users:
> 
> +  18 or 36 GB SCSI: system itselfe and about 20--25 GB /var for
>    incoming/outgoing mail (incl. virus scanning) and the more actively
>    used part of the cyrus mail store, quota of about 100 MB/user or
>    10 GB shared by the user.* hierarchy on it
> 
> +  120 GB IDE to keep another cyrus mail store partition (archive)
>    Users should move older mail from the default partition to
>    the archive. Some shared folders will probably reside on the IDE
>    discs, too. The archives will provide a quota of 1 GB/user.
> 
> Two identical 120 GB IDE discs should be used to keep and mirror the
> archive. The SCSI disc should be mirrored also (at least the /var
> partition), though I'm not sure yet whether it's better to use a
> second SCSI disc for that or if it's a good idea to divide the IDEs
> into partitions of 100 GB and 20 GB each, so that the SCSI disc can be
> mirrored to the 20 GB partitions on the IDEs.
> 
> Daily backups will probably be done to another 120 GB IDE disc. I'll
> use ext3fs for all partitions --- reiserfs or even xfs may have
> advantages, but I like ext3 more, and the expected number of files
> that have to be handled should be still ok for ext3.
> 
> Is this a reasonable setup, and can it reliably be done with LVM? Or
> is it better to use raidtools2 for it?
> 
> Or would you suggest to use hardware IDE RAID instead, maybe by
> forgoing SCSI?

Hi,

Your idea looks similar to what I'm intending to do with my next big
server. Some things come to mind:

- Hardware IDE Raid: Most so called hardware RAID are simply software
RAID, because the driver from the vendor does software RAID. Those
driver are often binary only and they do RAID worse than the Linux MD
driver does it. Until you want to go with true hardware RAID like 3ware,
stay away from it.

- I've been using LVM on top of software RAID0,1,5. I've been told that
the RAID function built in in LVM is not as good as Linux MD, YMMV.

- XFS on top of LVM/MD is very cool because you can grow volumes and
filesystems on the fully operating server. In fact, growing XFS can only
be done online. Unfortunately there were some issues with snapshotting
with XFS.

- ext3 on top of LVM/MD works well too. Snapshotting works well. Growing
filesystems have to be done offline. There are tools to grow online, but
this is dangerous.

Simon

> 
> Any suggestions are appreciated --- I don't know how flexible LVM can
> make things, so a totally different setup might be even better.
> 
> GH