RIP ext4. Allen Samuels Software Architect, Fellow, Systems and Software Solutions 2880 Junction Avenue, San Jose, CA 95134 T: +1 408 801 7030| M: +1 408 780 6416 allen.samuels@xxxxxxxxxxx > -----Original Message----- > From: ceph-devel-owner@xxxxxxxxxxxxxxx [mailto:ceph-devel- > owner@xxxxxxxxxxxxxxx] On Behalf Of Sage Weil > Sent: Monday, April 11, 2016 2:40 PM > To: ceph-devel@xxxxxxxxxxxxxxx; ceph-users@xxxxxxxx; ceph- > maintainers@xxxxxxxx; ceph-announce@xxxxxxxx > Subject: Deprecating ext4 support > > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
