Implement Cyrus IMAPD in High Load Enviromment

[Bron Gondwana]

On Tue, Sep 29, 2009 at 09:45:53AM +0200, Simon Matter wrote:
> What I'm really wondering, what filesystem disasters have others seen? How
> many times was it fsck only, how many times was it really broken. I'm not
> talking about laptop and desktop users but about production systems in a
> production environment with production class hardware and operating
> systems.

Well - we lost three drives in a 3TB RAID6 partition within 24 hours.
That was sad.  The third drive wasn't totally lost, just throwing enough
errors that we remounted the whole thing readonly and kept it around to
supplement the backup restores.

> Would be really interesting to get some of the good and bad stories even
> if not directly related to Cyrus-IMAP.

Honestly, the biggest thing is - I've got a unit I've just switched drives
in. It has 4 x 300GB 15kRPM drives in two RAID1 sets, and 8 x 2TB drives
in two RAID5 sets.  That's 12TB of data space plus a bit of room for meta.

Those 2TB drives spin at 7k2RPM, that's not that fast.  It takes weeks to
fill one of those things, and weeks again to copy data off.

Once you start talking multi-day downtimes to restore data, that's when your
customers take their business elsewhere, and fair enough.  Ok if you're a
university or business with a captive customer base, but not so nice if
you're trying to keep customers!

Bron.