Planet Ceph

Aggregated news from external sources

  • August 18, 2008
    Snapshots are now in the ‘unstable’ branch

    I’ve just merged the snapshot support into the unstable branch.  It’s not completely finished yet (garbage collection and handling for a number of corner cases is still missing), but provided you don’t actually create/destroy any snapshots, things will behave as before. I’m merging this now because there was relatively extensive surgery on the MDS to […]

  • July 24, 2008
    Snapshot progress

    If things seem a bit slow lately, it’s because I’ve been primarily working on implementing the snapshot mechanism for the last few weeks.  This is coming along pretty well: I can take snapshots and access snapshotted content.  The interaction with recursive accounting has been tricky because delayed propagation means changes may propagate into recent snapshot […]

  • July 11, 2008
    Next up: snapshots!

    One of the last intrusive additions I have planned is a flexible snapshot mechanism.  I haven’t been able to figure out how to map writeable snapshots onto the current object and metadata storage model, unfortunately, so it’ll be read-only snapshots for now.  Ceph snapshots will be significantly more flexible than what you find with WAFL […]

  • June 16, 2008
    Recursive accounting

    This is somewhat old news, but the recursive accounting changes have been merged into both the ‘unstable’ and ‘master’ branches, and the feature is documented in the wiki. I’m extremely curious what people think of this feature (useful? confusing?).  It takes liberties with two common behaviors of directories: first, with the “rbytes” mount option, the […]

  • May 23, 2008
    Stable (‘master’) branch updated

    I’ve just merged a bunch of recent changes into the ‘master’ branch in git.  The big items are lots of kernel client fixes improved stability of NFS re-export of a ceph client mount xattrs various OSD failure recovery fixes, and a corruption bug fix in EBOFS a big cleanup of the userspace client code, to […]

  • May 23, 2008
    Recursive accounting for size, ctime, etc.

    Watch the size on the directories: $ mkdir foo ; cd foo $ mkdir -p dir1/subdir $ mkdir -p dir2 $ echo 123456789 > dir1/file.10 $ echo 12345678901234 > dir1/file.15 $ echo 1234 > dir1/subdir/file.5 $ echo 12345678901234567890123456789 > dir2/file.30 $ find . -ls 1 drwxr-xr-x 1 sage sage 60 May 23 15:23 . 1 […]

  • May 7, 2008
    v0.2 Released

    The kernel client is holding up well under the latest round of testing, so I’ve cut a v0.2 release and am sending an announcement to LKML and linux-fsdevel. Notable in this release: fully functional and reasonably stable kernel client NFS re-export of a ceph client mount client metadata leases for strict client cache coherency and […]

  • April 21, 2008
    Kernel client update

    The Linux kernel client has stabilized to the point where you can untar and build a kernel source tree (and unmount it cleanly) without any problems.  Yay!

  • April 18, 2008
    POSIX file system test suite

    A few weeks back a POSIX file system test suite was announced on linux-fsdevel. Some 1700 tests of return values, error codes, and side effects for things like unlink, chmod, and so forth. The suite turned up a number of minor bugs in the MDS and client (mostly relating to things like legal file modes), […]

  • April 18, 2008
    Delayed capability release

    The Ceph MDS server issues “capabilities” to clients to grant them permission to read or write objects for a particular file. I’ve added a delayed release of capabilities after a file is closed, as many workloads will quickly reopen the same file. In that case, we can re-use our existing capabilities (and be assured by […]

  • April 8, 2008
    Well-behaved writeback

    We reached an exciting milestone for the Ceph kernel client this week: file data writeback is working, and well-behaved.  In particular, the speed of a tar file extraction is limited primarily by MDS latency for file creation.  File data is written asynchronously to OSDs in nice big I/Os (based on the striping parameters… 4 MB […]

  • March 24, 2008
    Client cache coherency

    I’ve been shying away from the question of how to manage the client metadata cache consistency for ages, now, under the assumption that it was going to complicate the client/MDS protocol and MDS significantly. Zach’s progress on CRFS got me thinking about it again, though, and I had a realization the other night that most […]