Planet Ceph

Aggregated news from external sources

  • January 30, 2009
    Some performance comparisons

    I did a few basic tests comparing Ceph to NFS on a simple benchmark, a Linux kernel untar.  I tried to get as close as possible to an “apples to apples” comparison.  The same client machine is used for NFS and Ceph; another machine is either the NFS server or the Ceph MDS.  The same […]

  • January 20, 2009
    POSIX file system test suite

    The unstable client (with all of the async metadata changes) is passing the full POSIX file system test suite again (modulo the question of whether chmod -1,-1 should be a no-op or update ctime).  We’re also surviving long dbench runs.  Progress!  I hope to push this all into the master branch after a bit more […]

  • January 12, 2009
    Asynchronous metadata operations

    The focus for the last few weeks has been on speeding up metadata operations.  The problem has been that the focus was first and foremost on reliability and recoverability.  Each metadata operation was performed by the MDS, and it was journaled safely to the OSDs before being applied.  This meant that every metadata operation went […]

  • December 16, 2008

    The last month has seen a lot of work on the storage cluster, fixing recovery related bugs, improving threading, and working out a mechanism for online scrubbing.  In this case, scrubbing is basically a low-level fsck of the object storage layer.  For each PG being scrubbed, the primary and any replica nodes generate a catalog […]

  • November 14, 2008
    v0.5 release sent to linux-fsdevel, -kernel

    I’ve tagged a v0.5 release, and this time sent the client portion in patch form to linux-kernel and linux-fsdevel for review.  We’ll see what happens!  It weights in a 20k lines of code, so I’ll be impressed if anyone decides to wade through it immediately. New in this release: Lots of bug fixes, especially in […]

  • November 6, 2008
    lockdep for pthreads

    Linux has a great tool called lockdep for identifying locking dependency problems.  Instead of waiting until an actual deadlock occurs (which may be extremely difficult when it is a timing-sensitive thing), lockdep keeps track of which locks are already held when any new lock is taken, and ensures that there are no cycles in the […]

  • October 7, 2008
    v0.4 Release

    I’ve tagged v0.4.  New in this release: Flexible snapshots (create snapshots of _any_ subdirectory) Recursive accounting for size, ctime, file counts Lots of client bug fixes and improvements, including asynchronous writepages, additional crc protection of network messages, sendpage (zero-copy writes where supported). The main new item in this release is the snapshot support.  Unlike snapshots […]

  • 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 […]