UBB.Developers Forums Community Development Programming MySQL and Server Configuration Disk speed

Anyone know a good way to find out if disks are a bottle neck?

Right now I'm running mysql for ubbthreads on a IDE software RAID 5 system. The drives are 7200rpm and run pretty well. In that system I have a 15k RPM SCSI drive as well.

I'm trying to figure out if purchasing a couple more SCSI drive and make it a raid5 would be worth it, hence the question on determining bottle necks.

CPU load now is between 30-40% on a Dual 1.1 PIII, and if going to SCSI gets me a bonus year, it's probably worth it. (already have 2GB Ram onthe system).

TIA

Fred

The disks may be the bottleneck, as you obviously have a good deal of ram and dual processors.. not the fastest, but still not too shabby either.

The best thing to check is to see whether or not UltraATA is setup on your IDE drives. Sometimes even if you have 66MB/s+ drives, they may only be set in PIO mode or DMA mode, hence keeping your data transfer rate at the maximum, 33MB/s.

Typically most providers will configure the servers to utilize the disks properly, but it is always worth checking to be sure. Here is an article that talks about disk performance with linux and how to get some information regarding your setup:

http://linux.oreillynet.com/pub/a/linux/2000/06/29/hdparm.html

Here are some other useful links:

http://www.faqs.org/docs/securing/chap6sec74.html
http://www.linuxgazette.com/issue79/punk.html

Of course, upgrading to a RAID SCSI setup will certainly help your read/write times, it may not be the only answer. How large of a database are you running? More than one site? How many users currently connected? Etc...

But that should get you started.

Thanks Jeremy, I'll have a look at that stuff tonight.

I don't remember exactly the size of the ubbthreads DB, but the sql dumps are about 1/2 GB. There are other DBs running, but not that busy. Users can max out around 150 logged in and another 150-200 in a 30minute period.

Sounds about like my site.. DB is upwards of a half gig, and typically about 100 users online, max of 134. I'm running mine on a single P4. 2.4GHz machine I believe it is, with a 7200 RPM drive as well with 1 gig of ram. Things seem to be still running smoothly as far as I can tell.

There are also a few other sites and databases on the server, but are small in comparison.

Dont use raid 5 buy another drive and use raid 10 a lot better for random database work

What's the difference between RAID 5 and RAID 10?

http://www.raid.com/04_01_00.html

All the raid levels explained in easy terms, for dummies like me, with pictures.

Thanks, that was a very informative page!