Clustering performance

[starscream]

I'm in the middle of a storage upgrade project removing legacy SAN stuff and replacing with Dell Powervault 220s. The PV220s are loaded with 14 15k 300GB SCSI drives and put into a cluster with 2 Dell Powervault 6450 running Windows 2003 Enterprise server. The controller cards are Perc 3/DC's.

I've got everything running fine, but the performance doesn't seem to be that great. Clustering forces you to use WRITETHRU within the Perc BIOS which I know is slower than WRITEBACK, but even so, I'm only getting speeds of 5-8MB/s which seems really slow to me.

Does this sound right to you guys, or could a be missing something?

EDIT : Forgot to say, I'm using RAID5 and have updated to the latest BIOS's for the servers/percs etc. Also, I've done 2 sites (with identical kit) so far and this seems to be the same for both, so I don't think its a fault.

 

[starscream]

This probably belongs in the storage section of the forum, how many spindles do you have in total and how are you measuring the speed? Raid5 is also one of the slowest raids round with Raid 1+0 being much faster but obviously at the cost of disc space.

Yeah I did think about putting it in storage, but I've noticed the sys admin types tend to hang out more in here.

Got 14 300GB disks in there (13 in the RAID5 arrays and a hotspare). Details of the PV220 here - http://www.dell.com/content/products/productdetails.aspx/pvaul_22xs?c=us&cs=28&l=en&s=dfb

I'm using an app called viceversa which mirrors data that is reporting the transfer rate, but I can check the MS performance monitor to make sure its not being misreported I guess.

Thanks for the help so far.