Large Installation

[snakes1100]

I'll touch on the drives, but you never did tell us all the server specs, this info is required as we dont know what all your running.

If you want top performance from the DB server, they should be in a Raid 10 Array, i would use SAS drives, that are 15k rpm, SCSI drives have the performance as well, but SAS drives will out perform them.

[shalsaid]

Yes we use SAS 15K

Seagate \ 300GB:SAS:15K RPM Cheetah \ ST3300655SS

The CPU is
Intel \ 2.13 GHz 1066FSB - Kentsfield \ Xeon 3210 (Quad Core)

RAM is 8G

we dont use RAID

On both servers

[snakes1100]

Is it Raid 10?

[shalsaid]

we dont use RAID

[snakes1100]

Well, thats a issue there, mysql loves Raid 10.

[y2ksw]

I'd say the disk is a little too small in order to have rapid access for 18 million posts + attachments. I estimate the database size about 130 GB, which is a very optimistic size (likely to be more), and about 50 GB of attachments. This would make a 300GB disk at 2/3 full and thus becomes already unefficient.

The suggested RAID configuration would give 2x5 disks of which 1x5 disks are serial and the other 1x5 array the backup (parallel). At 1.5 TB (at 300 GB each) the used space is about 2/15 or 14% which is just fine.

It may also work with a single drive, but please make sure to have daily or progressive backups. A disk failure may become a major issue if backups miss or lack quality, and data recovery from broken disks is very, very expensive ($10k+).

[shalsaid]

what if I use enterprise mysql would it help?

http://www.mysql.com/products/enterprise/server.html

Federated Storage Engine to create a single logical database from many physical servers

would that solve our problem?

thanks for your help

[y2ksw]

Inform yourself first (at mysql.com) ... it may solve the problems partly, but generally seen it makes no difference how your database is divided. It would be really best not to split the database at all and get a really good server, if performance is the main goal.