I was wondering if it had something to do with quota enforcement. The other possibility that occurs to me is if other clients are monitoring the system, or an admin pane (eg the dashboard) is displaying per-volume or per-client stats, they may be poking at the mountpoint and interrupting exclusive client caps? -Greg On Mon, Aug 15, 2022 at 8:19 PM Xiubo Li <xiubli@xxxxxxxxxx> wrote: > > On 8/9/22 4:07 PM, Robert Sander wrote: > > Hi, > > > > we have a cluster with 7 nodes each with 10 SSD OSDs providing CephFS > > to a CloudStack system as primary storage. > > > > When copying a large file into the root directory of the CephFS the > > bandwidth drops from 500MB/s to 50MB/s after around 30 seconds. We see > > some MDS activity in the output of "ceph fs status" at the same time. > > > > When copying the same file to a subdirectory of the CephFS the > > performance stays at 500MB/s for the whole time. MDS activity does not > > seems to influence the performance here. > > > > There are appr 270 other files in the root directory. CloudStack > > stores VM images in qcow2 format there. > > > > Is this a known issue? > > Is there something special with the root directory of a CephFS wrt > > write performance? > > AFAIK there is no special with the root dir. From my local test there is > not difference with the subdir. > > BTW, could you test it for more than once for the root dir ? When you > are doing this for the first time the ceph may need to allocate the disk > spaces, which will take a little time. > > Thanks. > > > > > Regards > > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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