On Tue, 16 Mar 2010, Tonmaus wrote:
AFAICS the CPU loads are only high while scrubbing a double parity pool. I have no indication of a technical misbehaviour with the exception of dismal concurrent performance.
This seems pretty weird to me. I have not heard anyone else complain about this sort of problem before in the several years I have been on this list. Are you sure that you didn't also enable something which does consume lots of CPU such as enabling some sort of compression, sha256 checksums, or deduplication?
running from currently. I am seeing CPU performance being a pain point on any "software" based array I have used so far. From SOHO NAS boxes (the usual Thecus stuff) to NetApp 3200 filers, all exposed a nominal performance drop once parity configurations were employed.
The main concern that one should have is I/O bandwidth rather than CPU consumption since "software" based RAID must handle the work using the system's CPU rather than expecting it to be done by some other CPU. There are more I/Os and (in the case of mirroring) more data transferred.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
