I picked up an old external SAS/3.0 Gbps DAS enclosure to tinker with. It has a built-in Adaptec AIC-9410 SAS controller with external SAS connectors (SFF-8088). I set up a RAID0 set with 4 (four) basic off the shelf SATAIII/6.0 Gbps 7200 RPM HDDs and then later another RAID0 set with 4 (four) basic off the shelf SATA/6.0 Gbps SSDs. I attached the enclosure to my test machine with a LSI SAS9201-16i HBA 6 Gbps HBA controller (in IT/initiator target mode) and HP SAS Expander (which has the external SAS/SFF-8088 connection). Using ATTO Disk Benchmark I got roughly 450 MB/s read & 425 MB/s write for the HDD set and 480 MB/s read and 450 MB/s write for the SSD set. Are these on par with real world throughput for SAS1/3.0 Gbps (which is essentially SATAII/3.0 Gbps)? If not, what's the bottleneck/issue?
P.S. - There are some details that I'm not 100% sure impact the above speeds...:
P.S. - There are some details that I'm not 100% sure impact the above speeds...:
- 2 (two) of the 4 (four) SSDs in the RAID0 group are rated at 340 MB/s read and 100 MB/s (the other two are rated 550 MB/s and 475 MB/s, read and write respectively)
- The HP SAS Expander is rated at 6.0 Gbps for SAS drives and 3.0 Gbps for SATA drives. I know the drives are all SATA, but I'm not sure how if it sees the RAID volumes the enclosure presents as SAS or SATA since it's coming over a SAS port