Hi yall!
for the last few days I have been developing a software to benchmark a mail server cluster. The reason for this is that first I couldn't find one online, second using sequential tests on any filesystem won't give you what's best for you because with e-mail everything is happening in parallel and you won't see if one option wins on parallelism (tar, rsync, cp, find, ls -la, etc all are sequential tests), and third is that there is no better way to produce a similar read/write IO pattern. This software will be released GPL next month.
Thursday I'll be arriving at my data center (at another continent by the way), I'll be there for 13 days and my main objective for these days is to put GlusterFS up running there. The current setup is not good enought and it doesn't scale anymore. Other things are secondary, although there are a few. Throughout those 13 days I will be using my software to study many many options for the storage servers, for example:
Filesystem options: Ext3, XFS, ZFS (OpenSolaris)
RAID options: RAID 10, RAID 5, RAID 6, RAID 0 + (ZFS:RAID-1, ZFS:RAID-Z, ZFS:RAID-Z2)
GlusterFS: 1.3/1.4, Unify/DHT, BDB/Posix, IO-Cache, Read-Ahead, Write-Behind
Network file systems: NFS/GlusterFS (splitting directories with NFS is a escape plan).
Besides other options involving e-mail hosting, like what RDBMS I should use to do user authentication, etc...
I have 4 nice mail servers (storage clients) and two nice storage servers (4TB each) available for the tests. My final setup is exactly the double (8 mail servers, 4 storage servers). Right now I have about 9k users checking their e-mails every 5 minutes, running with HA-NFS, but this setup is my current bottle-neck and it doesn't scale (I can't just add more storage servers). I expect to put 15k users on the new setup but I wish it could grow bigger.
Of couse I'll send all the results to the list, put on the wiki too (NFS x Best GlusterFS for mail storage, how is this going to end?). I would like to ask you devs and users a few questions:
(Devs and users) How do I get started with OpenSolaris and ZFS? What should I be looking for with my bechmarks? What do I have to study on ZFS performance optimization? I have no experience at all here.
(Devs) Can you send me an example on the DHT? The DHT is what I have always dreamt about, I'm really betting on it.
(Devs) I've seen by the changelog that the 1.4 tree development is going really fast. Bug are being fixed everyday and this is great! I hope I'll help to find a fix a few too in this process. So, say 1.4 is much much better for me (I'm betting on that), when do you guys expect an stable version? How easy is to migrate from 1.3-Unify+AFR+Posix to 1.4-DHT+AFR+BDB?
Thank you all for all the help!
Best regards,
Daniel van Ham Colchete
(IRC: vanham)
