Planet Ceph

Aggregated news from external sources

  • 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 […]

  • March 19, 2008
    File system creation and scaling

    I’ve spent the last week or so revamping the whole “mkfs” process and some of the machinery needed to adjust data distribution when the size of the cluster changes by an order of magnitude or more. The basic problem is that data is distributed in a two-step process: objects are first statically mapped into one […]

  • March 13, 2008
    Google Summer of Code

    We’re applying for the Google Summer of Code this year. Some project ideas are posted in the wiki, although of course it is by no means an exhaustive list. From what I’ve read, some of the most successful GSoC projects are proposed by the students. That said, there are lots of interesting projects on the […]

  • March 2, 2008
    Blog!

    I’m setting up this blog as a way to let people keep tabs on development progress. I’ve been periodically sending updates to the ceph-devel list, but I don’t think that’s the ideal venue for announcements, and it seems unlikely…

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