Hello, as others have reported in the past and now having tested things here myself, there really is no point in having journals for SSD backed OSDs on other SSDs. It is a zero sum game, because: a) using that journal SSD as another OSD with integrated journal will yield the same overall result performance wise, if all SSDs are the same. And In addition its capacity will be made available for actual storage. b) if the journal SSD is faster than the OSD SSDs it tends to be priced accordingly. For example the DC P3700 400GB is about twice as fast (write) and expensive as the DC S3700 400GB. Things _may_ be different if one doesn't look at bandwidth but IOPS (though certainly not in the near future in regard to Ceph actually getting SSDs busy), but even there the difference is negligible when for example comparing the Intel S and P models in write performance. Reads are another thing, but nobody cares about those in journals. ^o^ Obvious things that come to mind in this context would be the ability to disable journals (difficult, I know, not touching BTRFS, thank you) and probably K/V store in the future. Regards, Christian -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Fusion Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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