Equallogic ODX Transfers

Question

I have a general question regarding ODX on Equallogic arrays. I have a PS6100E Raid 6 (24 x 1TB 7200RPM). During an ODX transfer (70GB file copy from one iSCSI volume to another), the speeds are very erratic and only averaging about 175MBs. Performing the same file copy with ODX disabled, speeds were averaging around 200MBs. From SAN HQ: http://snag.gy/TsWu8.jpg ODX Transfer: http://snag.gy/8l6h3.jpg Non-ODX Transfer: http://snag.gy/j7VLi.jpg I'm a little surprised that I'm getting slightly higher data transfer rates with ODX disabled. Does Equallogic use the switching fabric when performing an ODX copy within the same array? Or is it handled completely within the array (when using a single array)? What are other people seeing for an ODX transfer on a PS6100 series (4 x 1Gbe ports per controller)?

ChuckFarah · Answer

yes the iscsi switch will be used (from the ports on the array perspective not the host ports) so the 1 Gige interface may bottleneck the overall bandwidth on the PS6100...also if you quantifying the transfer through the status display in windows that may be variable since the array responds with status every 3 seconds back to the host. Typically taking the total time is a better method for avg MB/s. which version of firmware do you have? and windows?

FluidFS

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