On 29/12/16 22:39, Peter Grandi wrote:
[ ... ] I now found out that performance of a 520s SSD is
around 180 times faster than a 530s SSD. [ ... ]
Well "performance" can be roughly the same, even if "speed" can
be very different.
http://www.sabi.co.uk/blog/15-two.html#151023
I'm not entirely sure what you mean to say here, I have a reasonably
well defined real life workload, (ie, single threaded, small random
writes)... I am measuring the same statistics across multiple devices
and comparing those numbers.
In addition, replacing the devices with others that showed an
improvement (measured during testing) in the real life system showed an
equivalent improvement (reduction) in end user complaints. So I feel
reasonably sure that I am "on the right track"....
Am I overlooking something else (very possible)?
520s: 70MB/s
530s: 0.4MB/s
....
fio --filename=/dev/sdb --direct=1 --sync=1 --rw=write --bs=4k
--iodepth=1 --runtime=60 --time_based --group_reporting
--name=IntelDC3510_4kj1 --numjobs=1
Arguably the 520s actually have no performance.
https://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/
I have seen this page, and all I can suggest is that the 480GB 520s
performs very different to the 60GB model. I see 70MB/s which is
significantly different to the listed 9MB/s on that page.
This page matches my results (comparatively) that the 520 performs much
better than the 535, though I don't have easy access to a 535 in order
to run my destructive tests.... but I did run similar tests on a 535,
and I ran the more thorough tests on the 530 and 540.
Regards,
Adam
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