Hello, Firstly, this is clearly a ceph-users question, don't cross post to ceph-devel. On Thu, 15 Oct 2015 09:29:03 +0800 hzwulibin@xxxxxxxxx wrote: > Hi, > > It should be sure SSD Journal will improve the performance of IOPS. But > unfortunately it's not in my test. > > I have two pools with the same number of osds: > pool1, ssdj_sas: > 9 osd servers, 8 OSDs(SAS) on every server > Journal on SSD, one SSD disk for 4 SAS disks. > Details. All of them. Specific HW (CPU, RAM, etc.) of these servers and the network, what type of SSDs, HDDs, controllers. > pool 2, sas: > 9 osd servers, 8 OSDs(SAS) on every server > Journal on SAS disk itself。 > Is the HW identical to pool1 except for the journal placement? > I use rbd to create a volume in pool1 and pool2 separately and use fio > to test the rand write IOPS。here is the fio configuration: > > rw=randwrite > ioengine=libaio > direct=1 > iodepth=128 > bs=4k > numjobs=1 > > The result i got is: > volume in pool1, about 5k > volume in pool2, about 12k > Now this job will stress the CPUs quite a bit (which you should be able to see with atop or the likes). However if the HW is identical in both pools your SSD may be one of those that perform abysmal with direct IO. There are plenty of threads in the ML archives about this topic. Christian > It's a big gap here, anyone can give me some suggestion here? > > ceph version: hammer(0.94.3) > kernel: 3.10 > > > > hzwulibin@xxxxxxxxx -- 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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