That doesn't make sense -- 50MB for 36 million files is <1.5 bytes each. How do you have things configured, exactly? On Sat, Apr 25, 2015 at 9:32 AM Adam Tygart <mo...@k-state.edu> wrote:
> We're currently putting data into our cephfs pool (cachepool in front > of it as a caching tier), but the metadata pool contains ~50MB of data > for 36 million files. If that were an accurate estimation, we'd have a > metadata pool closer to ~140GB. Here is a ceph df detail: > > http://people.beocat.cis.ksu.edu/~mozes/ceph_df_detail.txt > > I'm not saying it won't get larger, I have no idea of the code behind > it. This is just what it happens to be for us. > -- > Adam > > > On Sat, Apr 25, 2015 at 11:29 AM, François Lafont <flafdiv...@free.fr> > wrote: > > Thanks Greg and Steffen for your answer. I will make some tests. > > > > Gregory Farnum wrote: > > > >> Yeah. The metadata pool will contain: > >> 1) MDS logs, which I think by default will take up to 200MB per > >> logical MDS. (You should have only one logical MDS.) > >> 2) directory metadata objects, which contain the dentries and inodes > >> of the system; ~4KB is probably generous for each? > > > > So one file in the cephfs generates one inode of ~4KB in the > > "metadata" pool, correct? So that (number-of-files-in-cephfs) x 4KB > > gives me an (approximative) estimation of the amount of data in the > > "metadata" pool? > > > >> 3) Some smaller data structures about the allocated inode range and > >> current client sessions. > >> > >> The data pool contains all of the file data. Presumably this is much > >> larger, but it will depend on your average file size and we've not > >> done any real study of it. > > > > -- > > François Lafont > > _______________________________________________ > > 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 >
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