mirror_zfs/module
Matthew Ahrens faf0f58c69 Illumos 3835 zfs need not store 2 copies of all metadata
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

Description from Matt Ahrens's bug report at Delphix:

    Add a new zfs property, "redundant_metadata" which can have values
    "all" or "most".  The default will be "all", which is the current
    behavior.  Setting to "most" will cause us to only store 1 copy of
    level-1 indirect blocks of user data files.

Additional notes:

    The new man page section for this property states

        "The exact behavior of which metadata blocks
         are stored redundantly may change in future releases."

    and:

        "When set to most, ZFS stores an extra copy of most types of
         metadata. This can improve performance of random writes,
         because less metadata must be written."

    The current implementation is as described above in Matt's blog.
    It is controlled by a new global integer
    "zfs_redundant_metadata_most_ditto_level", currently initialized
    to 2. When "redundant_metadata" is set to "most", only indirect
    blocks of the specified level and higher will have additional ditto
    blocks created.

Ported by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2542
2014-07-31 09:49:34 -07:00
..
avl Add module versioning 2013-12-06 09:34:41 -08:00
nvpair Fix nvlist 'Bus Error' for Sparc 2014-01-09 15:50:15 -08:00
unicode cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
zcommon Illumos 3835 zfs need not store 2 copies of all metadata 2014-07-31 09:49:34 -07:00
zfs Illumos 3835 zfs need not store 2 copies of all metadata 2014-07-31 09:49:34 -07:00
zpios cstyle: Resolve C style issues 2013-12-18 16:46:35 -08:00
.gitignore gitignore: anchor entries at their respective directory 2013-04-02 10:50:17 -07:00
Makefile.in Add KMODDIR to install target 2013-03-06 15:46:40 -08:00