First, the concern: At work I am running a FreeNAS box for our teaching lab. It runs 7x HDDs in RAIDZ2 on a Core2Duo E8400 with 6 GB of RAM. The total usable storage pool is only like 700 GB, and it's using older SATA drives that passed with 92%+ performance on SMART. Amazing performance was never expected, but the performance I'm seeing is pretty slow. Big writes are slow, of course, but that's not the problem. We don't often write to the server, so 97%+ of traffic is reads. On an average day, we do about 200 GB of data sent. The FreeNAS box and the actual server (a PowerEdge 1950) use dual-nics in iSCSI multipathing in a round robin configuration. Actual bandwidth tests show we are able to reach 1.8 Gbps over CIFS (hard to believe, I know) if the data is simply written to RAM cache. This gives a realistic peak performance profile.
The problem, however, is that FreeNAS volume reads are only coming through at 30 MB/s when data is coming from the drives. Writes are about 25 MB/s. Using CrystalDiskMark on an iSCSI volume shows both NICs being utilized, but with the exact same performance profile. This confirms the performance concern as being volume related. (As a side note, small writes to the FreeNAS server shows peak network performance until the write exceeds 1.5 GB, which makes sense because FreeNAS caches writes to system memory. The slow reads make sense then because the data can't just be read from RAM, but instead has to be retrieved from the HDDs).
Is there a way to solve this performance issue? We aren't using deduplication or encryption either.
The problem, however, is that FreeNAS volume reads are only coming through at 30 MB/s when data is coming from the drives. Writes are about 25 MB/s. Using CrystalDiskMark on an iSCSI volume shows both NICs being utilized, but with the exact same performance profile. This confirms the performance concern as being volume related. (As a side note, small writes to the FreeNAS server shows peak network performance until the write exceeds 1.5 GB, which makes sense because FreeNAS caches writes to system memory. The slow reads make sense then because the data can't just be read from RAM, but instead has to be retrieved from the HDDs).
Is there a way to solve this performance issue? We aren't using deduplication or encryption either.