> On Feb 4, 2016, at 6:51 PM, Gregory Farnum <gfarnum@xxxxxxxxxx> wrote: > > I presume we're doing reads in order to gather some object metadata > from the cephfs-data pool; and the (small) newly-created objects in > cache-data are definitely whiteout objects indicating the object no > longer exists logically. > > What kinds of reads are you actually seeing? Does it appear to be > transferring data, or merely doing a bunch of seeks? I thought we were > trying to avoid doing reads-to-delete, but perhaps the way we're > handling snapshots or something is invoking behavior that isn't > amicable to a full-FS delete. > > I presume you're trying to characterize the system's behavior, but of > course if you just want to empty it out entirely you're better off > deleting the pools and the CephFS instance entirely and then starting > it over again from scratch. > -Greg I believe it is reading all the data, just from the volume of traffic and the cpu load on the OSDs maybe suggests it is doing more than just that. iostat is showing a lot of data moving, I am seeing about the same volume of read and write activity here. Because the OSDs underneath both pools are the same ones, I know that’s not exactly optimal, it is hard to tell what which pool is responsible for which I/O. Large reads and small writes suggest it is reading up all the data from the objects, the write traffic is I presume all journal activity relating to deleting objects and creating the empty ones. The 9:1 ratio between things being deleted and created seems odd though. A previous version of this exercise with just a regular replicated data pool did not read anything, just a lot of write activity and eventually the content disappeared. So definitely related to the pool configuration here and probably not to the filesystem layer. I will eventually just put this out of its misery and wipe it. Steve ---------------------------------------------------------------------- The information contained in this transmission may be confidential. Any disclosure, copying, or further distribution of confidential information is not permitted unless such privilege is explicitly granted in writing by Quantum. Quantum reserves the right to have electronic communications, including email and attachments, sent across its networks filtered through anti virus and spam software programs and retain such messages in order to comply with applicable data security and retention requirements. Quantum is not responsible for the proper and complete transmission of the substance of this communication or for any delay in its receipt. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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