In the same pool with compression enabled, I have a 1TB RBD filled with a 10GB /dev/urandom file repeating through the entire RBD. Deleting both of these RBDs didn't change the number of bluestore_extent_compress. I'm also pretty certain that's the same number I saw there before starting these tests, but I have no proof. There are 6 nodes with 5 OSDs in each. 5 of the nodes have bluestore OSDs and 1 has filestore (a part of the test was to see the behavior of a pool with compression enabled with filestore and bluestore OSDs in it.
On Tue, Jun 26, 2018 at 10:07 AM Blair Bethwaite <blair.bethwa...@gmail.com> wrote: > Hi, > > Zeros are not a great choice of data for testing a storage system unless > you are specifically testing what it does with zeros. Ceph knows that other > higher layers in the storage stack use zero-fill for certain things and > will probably optimise for it. E.g., it's common for thin-provisioning > systems to not actually store runs of 0's (they'll still return them when > read). I don't know what Ceph does in this specific case, but I could > imagine it allocating relevant space within the RBD object-map, but never > bothering to send anything to the actual objects. > > Also, note that the description of bluestore_extent_compress is "Sum for > extents that have been removed due to compression", so sounds to me like > something is working. Perhaps you can provide for detail of the overall > stats, cluster config, and whether anything else is stored in it? > > On Tue, 26 Jun 2018 at 23:53, David Turner <drakonst...@gmail.com> wrote: > >> ceph daemon osd.1 perf dump | grep bluestore | grep compress >> "bluestore_compressed": 0, >> "bluestore_compressed_allocated": 0, >> "bluestore_compressed_original": 0, >> "bluestore_extent_compress": 35372, >> >> I filled up an RBD in a compressed pool (aggressive) in my test cluster >> with 1TB of zeros. The bluestore OSDs in the cluster all show similar to >> this. Am I missing something here? Is there any other method to >> determining compression ratios? >> >> On Tue, Dec 5, 2017 at 1:25 AM Rafał Wądołowski < >> rwadolow...@cloudferro.com> wrote: >> >>> Finally, I've founded the command: >>> >>> >>> ceph daemon osd.1 perf dump | grep bluestore >>> >>> >>> And there you have compressed data >>> Regards, >>> >>> Rafał Wądołowski >>> >>> >>> http://cloudferro.com/ >>> On 04.12.2017 14:17, Rafał Wądołowski wrote: >>> >>> Hi, >>> >>> Is there any command or tool to show effectiveness of bluestore >>> compression? >>> >>> I see the difference (in ceph osd df tree), while uploading a object to >>> ceph, but maybe there are more friendly method to do it. >>> >>> >>> >>> _______________________________________________ >>> ceph-users mailing list >>> ceph-users@lists.ceph.com >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >>> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@lists.ceph.com >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > > > -- > Cheers, > ~Blairo >
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