Hi, The results look strange to me...
To begin with, it's strange that read and write performance differs. But the thing is that a lot (if not most) large Seagate EXOS drives have internal SSD cache (~8 GB of it). I suspect that new EXOS also does and I'm not sure if Toshiba has it. It could explain the write performance difference in your test.
Try to disable Seagates' write cache with sdparm --set WCE=0 /dev/sdX and see how the performance changes. If there is an SSD cache you'll probably see an increase in iops. Due to the nature of Bluestore and at least with an external block.db on SSD the difference is like ~230 iops vs ~1200 iops with iodepth=1. This is the result for ST8000NM0055.
Also it's strange that read performance is almost the same. Can you benchmark the drive with fio alone, without Ceph?
Hi, we ran some benchmarks with a few samples of Seagate's new HDDs that some of you might find interesting: Blog post: https://croit.io/2020/01/06/2020-01-06-benchmark-mach2 GitHub repo with scripts and raw data: https://github.com/croit/benchmarks/tree/master/mach2-disks Tl;dr: way faster for writes, somewhat faster for reads in some scenarios Paul -- Paul Emmerich Looking for help with your Ceph cluster? Contact us at https://croit.io Looking for Ceph training? We have some free spots available https://croit.io/training/4-days-ceph-in-depth-training croit GmbH Freseniusstr. 31h 81247 München www.croit.io [1] Tel: +49 89 1896585 90 Links: ------ [1] http://www.croit.io _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
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