On Sun, Dec 8, 2013 at 8:33 PM, Mark Kirkwood <mark.kirkwood@xxxxxxxxxxxxxxx> wrote:
I'd suggest testing the components separately - try to rule out NIC (and switch) issues and SSD performance issues, then when you are sure the bits all go fast individually test how ceph performs again.
What make and model of SSD? I'd check that the firmware is up to date (sometimes makes a huge difference). I'm also wondering if you might get better performance by having (say) 7 osds and using 4 of the SSD for journals for them.
Thanks, Mark.
In my haste, I left out part of a paragraph... probably really a whole paragraph... that contains a pretty crucial detail.
I had previously run rados bench on this hardware with some success (24-26MBps throughput w/ 4k blocks).
ceph osd bench looks great.
iperf on the network looks great.
After my last round of testing (with a few aborted rados bench tests), I deleted the pool and recreated it (same name, crush ruleset, pg num, size, etc). That is when I started to notice the degraded performance.
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