Hi Chirstian,
My configuration is as follows:
Two nodes: node0 (10.10.0.23), node1(10.10.0.24)
node0: Monitor, MDS, OSD0 in /dev/sdd1
node1: OSD1 in /dev/sdd1
The cephfs is mounted using: mount.ceph 10.10.0.23:6789:/ /mnt/mycephfs/
After finishing configuration (PGs are active+clean), I use the iostat cmd to
monitor the /dev/sdd1 in node0.
The iostat shows that there are write I/Os for about 15minutes. Then there are
no I/Os in the OSDs.
I am not sure where these write I/Os come from.
Thanks.
Best regards,
Fei Xia
> 在 2015年12月14日，11:58，Christian Balzer <ch...@gol.com> 写道：
>
>
> Hello,
>
> On Mon, 14 Dec 2015 11:46:43 +0800 xiafei wrote:
>
>> Hi all,
>> I have a question about the I/O of cephfs.
>> I configure cephfs with 2 OSDs, and 300PGs in two HDDs. Then I use the
>> iostat (iostat -kx 1 /dev/sdd1) to monitor the I/Os of the HDDs
>> (/dev/sdd1). The result is as follows:
>>
>>
>> The iostat shows that there are write requests every second. However I
>> do not execute any applications. What the source of the write I/O?
>>
> That's why you use atop and/or iotop to determine what program is writing
> to the disks.
>
> If it is indeed Ceph (ceph-osd process) writing to the disk then the
> question is indeed what causes that.
> I have no experience with CephFS, but quiescent RBD volume (mounted VM
> images) does not produce I/O by itself.
>
> You say that you're not running any application, but is the CephFS mounted
> somewhere?
>
> Regards,
>
> Christian
> --
> Christian Balzer Network/Systems Engineer
> ch...@gol.com Global OnLine Japan/Rakuten Communications
> http://www.gol.com/
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