[Dovecot] OT - small hd recommendation

[Emmanuel Noobadmin]

On 8/31/11, Daniel L. Miller <dmiller at amfes.com> wrote:
> I'm seeing some warnings & errors in my logs & dmesg - and Google tells
> me this can the result of several factors, including the hard drives.  I
> haven't seen any SMART warnings as yet - but I am getting a little
> nervous and thinking about upgrading the storage.

Possible to post some of those error messages?

> As part of the potential upgrade, I'm considering changing to RAID6 -
> seems a bit more efficient use of space.  I see no reason for SSD - I

It might be more efficient but you'll take a 3x IOPS penalty for
writes vs RAID 1/10. Depending on your exact workload, it is most
likely going to be a bad idea since you mention that you don't
actually need more space.

> think a set of reasonable 7200rpm drives should be just fine.  What I
> don't know is, compared to my current 4 drive RAID10 with SATA 1.5,
> would even a single SATA 3 drive be comparable in terms of seek
> performance?  Should I stick with the RAID-10?

Seek performance is largely a matter of I/O latency, SATA 3 only gives
you more bandwidth to play with. A SATA 3 4200RPM HDD will seek slower
than a SATA 1 7200RPM HDD.

For random I/O, more spindles/drives are usually the way to deal with
it, like others suggested, splitting your drives into RAID 1 nodes and
balancing different workloads on each node is probably your best bet
if you don't mind doing it manually.