We have an ATTO R380 SAS RAID controller in a Windows Server 2003 HP DL-160 server with 8 700GB Seagate 7200.12 drives.
It's configured as a RAID 5 array. ATTO Config says all drives are healthy and we see consistent drive write/read rates accross the drives.
The problem is, when transferring files from the array to local C: drive or even over our 1GB LAN, performance is very inconsistent and quite poor sometimes.
For instance, some files will copy at over 100MB/sec while some will copy as low as 10MB/sec, fluctuating between 10MB-35MB/sec all over the place.
I know RAID 5 isn't good for write peformance, but what could be causing this weird inconsistent read performance?