Sometime ago, i posted a message asking whether i could expect to see a good results for IOPS and latency performance using SSD drives in the Synology 1511+. As we all know, SSD is very well known for superb IOPS performance over mechanical drives, so for applications which demand high IOPS, that usually would require an elaborate SAS SCSI SAN can be achieved using lower end hardware, and a simple high reliability SSD (or two).
I have recently installed an OCZ Vertex 4 256mb ssd in my Synology 1511+ NAS, to use as my block level iscsi data store for my VM Ware Cluster.
Anyway, this drive is capable, connected natively to a system with SATAIII, at achieving 445mb read and 457mb sequential write, and iops with 4k64thread test on AS SSD 86,000 read iops and 76,000 write (http://www.guru3d.com/article/ocz-verte ... -review/14
Clearly, installing this in a NAS with SATAII is ofcourse going to impact these metrics, as is, connecting over a single 1GBps connection, but still, i should still see a vast improvement in IOPS, and max out my 1GBps connection.
Well, certainly, the results are interesting
Over a single 1GBps connection, I am getting a more modest 102mb/s read and 110 mb/s write, and 9269 read iops and 8842 write with the 4k64thread test on AS SSD and 0.6ms read and 0.5ms write latency
IOPS results are very impressive over a mechanical drive. It would take ALOT of VMS, or exchange servers to come anywhere near that demand. To put that in persepctive a single SATA 7200rpm HD will achieve 75 IOPS, and a 10,000rpm SAS drive 175 IOPS.
To put that in perspective: -
An IBM DS5300 SAN with 16x 15k 3.5" drives will achieve 3500IOPS (100% random 4k) and have a latency of 4.2ms. That SAN would be well over £6,000 including disks.
While i am pleased, i am keen to try and improve my IOPS performance even more, and also, understand why my IOPS performance should not be higher still.
Where would my bottlenecks be do you think? While i know my network interface could affect throughput (i am getting around 118mb/s read/write), i did not think that it would necessarily be limiting IOPS.
I have been using AS SSD tool for benchmarking.