On 4/20/2013 6:26 PM, Andrei Banu wrote: > They are connected through SATA2 ports (this does explain the read speed > but not the pitiful write one) in AHCI. These SSDs are capable of 500MB/s, and cost ~$1000 USD. Spend ~$200 USD on a decent HBA. The 6G SAS/SATA LSI 9211-4i seems perfectly suited to your RAID1 SSD application. It is a 4 port enterprise JBOD HBA that also supports ASIC level RAID 1, 1E, 10. Also, the difference in throughput your show between RAID maintenance, direct device access, and filesystem access suggests you have something running between the block and filesystem layers, for instance LUKS. Though LUKS alone shouldn't hammer your CPU and IO throughput so dramatically. However, if the SSDs do compression or encryption automatically, and I believe the 840s do, the LUKS encrypted blocks may cause the SSD firmware to take considerably more time to process the blocks. -- Stan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
