Harley Gorrell wrote:
I do wonder what accounts for the improvement -- seek time, transfer rate, disk cache, or something else? Does anywone have a dtrace script to measure this which they would share?
You might also be seeing the effects of defect management. As drives get older, they tend to find and repair more defects. This will slow the performance of the drive, though I've not seen this sort of extreme. You might infer this from a dtrace script which would record the service time per iop -- in which case you may see some iops with much larger service times than normal. I would expect this to be a second order effect. Meanwhile, you should check to make sure you're tranferring data at the rate you think (SCSI autonegotiates data transfer rates). If you know the model number, you can get the rotational speed and average seek times to see if that is radically different for the two disk types. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
