Linux server, high disc io- can this be done?
 

hi,

I have a server with 3 x 500 gig drives. (It has only around 300gigs of data being used.)

currently only 2 drives are being used. 1drive is primary and the other is just backing up the data from the first drive. 3rd drive not really used or mounted at the moment.

I have been told the site is failing due to high disc io. There are 3 domains being used on there. The data is not critical and i have local backups.

I was wondering if it is possible on a server to allocate 1 domain to each of the 3 drives? so splitting the load over 3 drives, each domain is actually using rought the same BW.

Is this possible ? since the rest of the resourses like memory and cpu are not used much.

Would using raid be a better option ?and if so which raid to use for fastest speed and highest tolerance to disc io considering i have 3 drives and no real need of backups?

I have been told raid is going to cost quite a bit more so i am hoping to be able to just put 1 domain on each drive thus splitting the load that way if possible ,or if it will even be effective.

thanks:)

You're an idiot.

change from SATA to SAS drives.

You're a pest.

Why not ask your hosting support for options....

hi,

Yeah i have asked on the ticket, just waiting for a reply - can take sometime depending on if they're busy. Just wanted to hear other ideas. SAS drives may work like someone suggested, or if i can't split the domains on to different drives in the server then i will probably just go for the hardware raid option. Another person mentioned ssd drives, just reading up on those now, but the storage size seems rather small.

TBh since i know nothing about server admin, i can't really know if what they suggest is the best option. They seemed to be unable to cure the server crashing once it had 300 max connections. I got another person to check on the server and he simply made some adjustments in the apache build and now it runs fine. He turned off some stuff that wasn't needed. He suggested i scrap apache altogether for a more efficient method like lighttpd or some other one, however i really need cpanel and whm or else i'd be stuck. So for now apache will be ok but if the site grows i guess i will have to learn to live without those and adopt lighttpd.

A long time ago - before i had this disc io issue, someone mentioned they had had the same problem and simply split his domains up and put them on different drives and cured his io issue. That's the reason i just asked here, maybe that is a common solution, because if i used raid, then if 1 drive breaks i will lose all the data for all 3 domains, however with spreading the domains on different drives i would only lose 1 domain, and maybe the os would still work if it was not the primary drive that failed. I was told discs under high load constantly are likely to fail at some point.

sure can be done .. pretty standard.
Name your 2 other drives ( like home2 and home 3 ).
Then create the domain account accordingly , pointing to the respective drive.

Will help a bit ...

thanks for that, i'm going to give it a try and see if it cures the problem:)

Depends what the I/O is caused by, if it's all MySQL queries then shifting a site's HTML, scripts and logs to another drive will probably make no difference...

... and if it is all MySQL, you can probably find a way to optimize your queries or database structure in order to reduce load...

hi,

The server is only used for serving movie files, there is no database usage at all.
The files are not that large 40megs max. I'd say only around 50 files are ever popular at one time. I'm reading it maybe possible to push a lot of that into ram using some apache mod. The ram is not really taxed much at all.

Oh well time to learn a little bit about server admin, if i even knew how to command ssh im sure i could resolve some issues and reboot when i can't reach the site via whm.

Looking at an easy apache guide to see what could be done that way that could take some stress off of the drives also maybe.

Definitely get rid of that bloated cpanel.
Use a fine tuned apache or lighttpd.
Split the IO load among the three disks.
Add more ram (as much as you afford), it will be used for caching in favor of IO load.

SSD's work good for high IO

try using zfs and an ssd drive for caching

depending on the IO.. you need some DAMN fast ssd's that wont do the sync() or flush() on the ssds. Caching on the ssds is great if your ssd drive plays nicely with zfs. A ssd that plays nicely with zfs is ungodly expensive. zfs's nvram on drive cache flushing is what kills it.