Wednesday, December 2, 2009

The noise of 1'000'000 inactive mailboxes

We have now migrated all inactive mailboxes (some may obviously be active again) to one 7410 Cluster.

What you can see is the IO generated by these boxes. Even if the mailboxes are abandoned they receive mails (spam, newsletters etc.)

Storage2/HDD4 and storage2/HDD8 are again the mirrored SLOG devices. As we can see here, they don't have any problems at all with the write load. If you look at all the other HDDs you see the low IOPS numbers



Looking at how many bytes per seconds are going through the disks we can see that the SLOGs are busy collecting all synchronous bits and bytes.

The slow 1TB disks get about ~700k of data per second. Looking at e.g. HDD11 we see a low number of IOPS. I would guess the average IO size is about 60-70kB. As a reference, an email is around 4k to 8k.



What this means: We get larger IOs to the disk thanks to the slog.

Thanks, mighty Logzilla :-)

2 comments:

Jean-Fran├žois said...

Very cool! We're about to migrate all of our corporate emails from a big NetApp F840 to a single 7410 /w 12 disks and 2 readzillas. After reading your post, I hope our mirrored pool can provide enough performance to handle the load since we do not have slog disks.

Thanks for sharing this with us!

Mika said...

I think if you go mirrored, your basics are fine for an email platform.

Depending on your workload, you can still add a SSD Based ZIL to your setup.

You will find it out with analytics later :-)