Problem: very slow disk access + very high load during disk access.
System: Dual Opteron, SuSE professional 9.2 64-bit, default SMP-kernel 2.6.8-24.11, SATA-RAID from 3ware with 3w-9xxx driver version v2.26.02.001 (From SuSE 9.2), RAID is the only "disk" in system and we have LVM on top of it (so we can change the sizes of the partitions later on.)
Example1: currently one java process reading data from file. Java get's 85-100% CPU time and load is at 6-7.5. Nothing else. Example2: yesterday, I copied data from another server (Dual Opteron SuSE 9.0) over NFS mount with cp -command. Load was at 2.5-3 and at the top of top listing I had nfsd processes with 1-2% CPU load each. Data transfer rate was only 2.2Mb/s and the servers were connected with Gigabit lan! Example3: From old RH server the file transfers resulted in high loads (4-7) during rsync copying - so it's not the "other" servers fault.
What's wrong? And what can I do about it?