Recently I connected LSI SAS 3442E-R and two HP SAS 600GB 10k HDD. My motherboard is AsRock Z97 Extreme6. Disk are configured as JBOD, no raid.
Linux lspci shows:
0b:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E PCI-Express Fusion-MPT SAS (rev 08)
Simple read test on single drive:
dd of=/dev/null if=/dev/sdh1 bs=1M count=5000
gives me speed 150MB/s
Adding in parallel:
dd of=/dev/null if=/dev/sdi1 bs=1M count=5000
Makes speed to drop to 100MB/s on sdh and gives speed 100MB/s on sdi. When I stop reading from one hd then speed on another raises to 150MB/s.
It looks like max speed of hard drive is 150MB/s but controller cannot do more than 200MB/s which is I think quite slow as for PCIe x4 card.
Anyone had similar problems? Any hints what can I do to improve performance?
