Hi Everyone,
Since you shared with me and it helped me out, I thought I would share back.
Our environment is VMware vSphere (ESX 4) with HP GB switches to a single Sun 7110. The servers are Sun X4150's with 32 GB RAM and 2.83 GHz Xeon CPU's. I have vlanned off the storage onto private network, but I have not teamed anything for this test. All tests were done with a single NIC from the servers and a single NIC on the 7110. The version of firmware on the 7110 was 2010.02.09.0.0,1-1.9
For IOMeter, I used the same icf file listed at the front of this thread. I tested from within a Windows 2003 VM and I didn't format the partition in Windows 2003. There were no other VM's accessing the Sun 7110 at the time of the tests.
Also...some information about how the Sun 7110 is setup for the tests:
For NFS - Data Dedupe is off, Data Compression is off, Synchronous Write Bias is set to Throughput and Database Record size is 128K
For iSCSI - Data Dedupe is off, Data Compression is off, Synchronous Write Bias is set to Throughput, Block sizes set to 64K and turned Write Cache on.
Obviously if you turn things like Data Dedupe on...it is gonna slow things down a bit.
I thought a comparison of NFS and iSCSI would be good, plus a comparison of Double Parity Raid to RAID 10 (mirrored). You know that mirrored should be faster, but how much faster...will it be worth it to you? This may help you decide.
So....for Double Parity Raid-
NFS:
Total I/O's per Second: 323.13
Total MB's per Second: 3.44
Average I/O Response Time: 3.0941
Maximum I/O Response Time: 330.4260
% CPU Utilization: 1.18
iSCSI:
Total I/O's per Second: 2648.69
Total MB's per Second: 28.61
Average I/O Response Time: 0.377
Maximum I/O Response Time: 475.4195
% CPU Utilization: 5.51
Mirrored (RAID10)-
NFS:
Total I/O's per Second: 557.49
Total MB's per Second: 5.77
Average I/O Response Time: 1.7932
Maximum I/O Response Time: 513.4279
% CPU Utilization: 1.58
iSCSI:
Total I/O's per Second: 2211.62
Total MB's per Second: 24.31
Average I/O Response Time: 0.4516
Maximum I/O Response Time: 1719.4337
% CPU Utilization: 4.68
Obviously the write cache is having a significant effect. So...I did one last test with iSCSI with the Write Cache disabled. Also..interestingly, the RAID10 iSCSI performance was not higher with Write Cache enabled. Notice that the response time with iSCSI with Write Cache enabled is much faster than NFS. The other problem I have with the Write Cache is I am not convinced that the above numbers would be accomplished during "real world" usage - especially after the cache is full.
Here are the results of iSCSI with Write Cache disabled.
iSCSI RAID10 - Write Cache Disabled
Total I/O's per Second: 638.14
Total MB's per Second: 6.82
Average I/O Response Time: 1.5665
Maximum I/O Response Time: 215.4945
% CPU Utilization: 2.04
iSCSI Double Parity Raid - Write Cache Disabled
Total I/O's per Second: 120.50
Total MB's per Second: 1.29
Average I/O Response Time: 8.2981
Maximum I/O Response Time: 1001.3984
% CPU Utilization: 1.03
So...without the cache....RAID10 is still faster, but Double Parity Raid looks bad with iSCSI compared to NFS.
So...who is the winner would depend on what you need - if you need space and go with RAID6 (Double Parity Raid), then NFS is the winner. If you want the best performance and can sacrifice space...then iSCSI with RAID10 is better.
Jim