Post by Moi on Mar 3, 2008 8:46:21 GMT 7
G'day All,
Perhaps it's just me but has anyone else noticed the difference in write performance between iSCSI and SMB on the 5200?
I've done lots of tests with a single 1GB test file (different jumbo frame size, enabling/disabling caching) and the pattern is always the same.
My expectation are that for a single large file copy, the read and write performance between iSCSI and SMB should be similar.
Read performance between the two, as expected, are similar. However, the write performance of iSCSI is consistently lower than SMB
Obviously changing the jumbo frame size and caching changes the results slightly but the same PATTERN remains - iSCSI write performance (eg. 14 MB/s) is ALWAYS much lower than SMB (eg. 22 MB/s). I give an example to show the difference is not small.
Testing was done by copying 1x1GB file using a batch file so timings are alot easier. PC is XP SP3 RC2 connected via 1Gb NIC to N5200 with 5 (500GB) disk RAID5. iSCSI parition is 99% (1.8TB) and SMB partition is 1% (18GB).
Has anyone else noticed the same thing? Is the assumption correct that for a single large file copy, the read and write performance should be similar between iSCSI and SMB? Is the difference in write performance just NTFS overhead?
Cheers
Teck
Perhaps it's just me but has anyone else noticed the difference in write performance between iSCSI and SMB on the 5200?
I've done lots of tests with a single 1GB test file (different jumbo frame size, enabling/disabling caching) and the pattern is always the same.
My expectation are that for a single large file copy, the read and write performance between iSCSI and SMB should be similar.
Read performance between the two, as expected, are similar. However, the write performance of iSCSI is consistently lower than SMB
Obviously changing the jumbo frame size and caching changes the results slightly but the same PATTERN remains - iSCSI write performance (eg. 14 MB/s) is ALWAYS much lower than SMB (eg. 22 MB/s). I give an example to show the difference is not small.
Testing was done by copying 1x1GB file using a batch file so timings are alot easier. PC is XP SP3 RC2 connected via 1Gb NIC to N5200 with 5 (500GB) disk RAID5. iSCSI parition is 99% (1.8TB) and SMB partition is 1% (18GB).
Has anyone else noticed the same thing? Is the assumption correct that for a single large file copy, the read and write performance should be similar between iSCSI and SMB? Is the difference in write performance just NTFS overhead?
Cheers
Teck