Hi Sage, I suspect most people nowadays run tests and develop on ext4. Not supporting ext4 in the future means we'll need to find a convenient way for developers to run tests against the supported file systems. My 2cts :-) On 11/04/2016 23:39, Sage Weil wrote: > Hi, > > ext4 has never been recommended, but we did test it. After Jewel is out, > we would like explicitly recommend *against* ext4 and stop testing it. > > Why: > > Recently we discovered an issue with the long object name handling that is > not fixable without rewriting a significant chunk of FileStores filename > handling. (There is a limit in the amount of xattr data ext4 can store in > the inode, which causes problems in LFNIndex.) > > We *could* invest a ton of time rewriting this to fix, but it only affects > ext4, which we never recommended, and we plan to deprecate FileStore once > BlueStore is stable anyway, so it seems like a waste of time that would be > better spent elsewhere. > > Also, by dropping ext4 test coverage in ceph-qa-suite, we can > significantly improve time/coverage for FileStore on XFS and on BlueStore. > > The long file name handling is problematic anytime someone is storing > rados objects with long names. The primary user that does this is RGW, > which means any RGW cluster using ext4 should recreate their OSDs to use > XFS. Other librados users could be affected too, though, like users > with very long rbd image names (e.g., > 100 characters), or custom > librados users. > > How: > > To make this change as visible as possible, the plan is to make ceph-osd > refuse to start if the backend is unable to support the configured max > object name (osd_max_object_name_len). The OSD will complain that ext4 > cannot store such an object and refuse to start. A user who is only using > RBD might decide they don't need long file names to work and can adjust > the osd_max_object_name_len setting to something small (say, 64) and run > successfully. They would be taking a risk, though, because we would like > to stop testing on ext4. > > Is this reasonable? If there significant ext4 users that are unwilling to > recreate their OSDs, now would be the time to speak up. > > Thanks! > sage > > _______________________________________________ > Ceph-maintainers mailing list > Ceph-maintainers@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-maintainers-ceph.com > -- Loïc Dachary, Artisan Logiciel Libre _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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