ZFS: Worse read performance on striped mirror vdevs vs. striped single-disk vdevs

Glad you fixed it. Would seem to me to indicate that ZFS is pretty broken performance wise with prefetch disabled. I don't have any systems with prefetch disabled but a good one to know anyway...

cheers Andy.
 
Still questions to be answered such as why prefetch disabled doesn't affect non-mirrored performance in the same way.

For what it's worth I did your tests and got same results. Not sure why people think it needs to be top end hardware to be a valid test.

Problem with prefetch on however it rapes random i/o performance and starves writes. So it's give and take. When using db files it kills performance.

Ideally I would like to see prefetch settable per fileset like on solaris.
 
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