Time for a new mailserver, then.
In an ideal world, I’d be putting the following on my shopping list:
HP DL380 G5, dual 2.67 GHz Xeon 5150 CPUs, 8 GB RAM, 8x 36 GB 2.5” 15k rpm SAS disks- for the main mail server, anti-spam&virus, the mail queue (a large number of low-capacity 2.5” disks is the best route to achieving ultra-low seek times, which is important for randomly-accessed data like email), and sending our weekly mailshots.
HP DL320s, single 2.67 GHz Xeon 3070 CPU, 4 GB RAM, 12x 300 GB 3.5” 15k rpm SAS disks- nfs server for users’ Maildirs, and the customer care mail database.
DL140 G3, dual 2.67 GHz Xeon 5150 CPUs, 8 GB RAM, 2x 100 GB 7.2 krpm SATA disks (for booting from only) x2- user-facing servers - the first hosting a number of Xen instances for people to read mail using mutt or adjust their procmail setups, as well as pop3 and imap servers, and the second running webmail and the web frontend for the customer care mail system.
mm, tasty.
Unfortunately, I don’t have a budget of fifteen grand to spend on the above, so I’m going to make do with just the one box. In fact, it’s worse than that, as I’m also going to have to use this machine as a replacement for our ftp server, our “friends’n’family” webserver, and as a backup server (connected to a nice lto2 tape array).
As a result, I plumped for the following:
HP DL320s, single 2.67 GHz Xeon 3070 CPU, 4 GB RAM- with an upgrade to a 512 MB battery-backed write cache
2x 72 GB 15k rpm 3.5” SAS disks
- a RAID 1 array for the mail queue and system partitions
10x 250 GB 7.2k rpm 3.5” SATA disks
- for users’ Maildirs
Total price was about £3,000 - a fifth of the cost of doing it right.
Meet flurry, our new mailserver
Things won’t be so awful for our technical staff - I’ll export their Maildirs to their own Xen instances on our big development server, laganside - so they can read their mail nice and quickly there. And I’ll probably inject the half-million message mailshots from infuse, a Xen instance elsewhere on our network. Even so - the new setup will merely provide a noticeable improvement to our users, rather tham being “zomg ultra-turbo-plus-plus!”. bah!
My task for the rest of week is to thoroughly benchmark the new machine, dubbed flurry. In particular, I’m interested to see the difference in speed between the various disk array setups that are open to me - JBOD (2.5 TB available), RAID 1+0 (1.25 TB available), RAID 5 (2.25 TB available), and RAID 6 (2.0 TB available).
My instinct is to go for either JBOD or RAID 6 - two disk failures will kill a RAID 5 array, and has a 50% chance of killing a RAID 1+0. With that number of disks, from the same manufacturer (a number of different batches, though), and subject to the same physical environment, the chances of experiencing multiple disk failures is higher than I’d like. I’m willing to be persuaded otherwise if the performance penalty for RAID 6 turns out to be huge, though.
Anyway, flurry has now been running memtest86+ for just over 24 hours, so it’s time for me to go start the benchmarking. hurrah!
