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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "DiskSetup" by SteveLoughran
Date Wed, 20 May 2009 13:13:12 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The following page has been changed by SteveLoughran:

The comment on the change is:
mention atime and how hadoop doesn't care for it.

  Pass a list of disks to the dfs.data.dir parameter, Hadoop will use all of the disk that
are available.
- == Underlying File System ==
+ == Underlying File System Options ==
+ If mount the disks as noatime, then the file access times aren't written back; this speeds
up reads. There is also relatime, which stores some access time information, but is not as
slow as the classic atime attribute. Remember that any access time information kept by Hadoop
is independent of the atime attribute of individual blocks, so Hadoop does not care what your
settings are here. If you are mounting disks purely for hadoop, use noatime.
  === Ext3 ===
  It's widely believed that Yahoo! use ext3. Regardless of the merits of the filesystem, that
means that HDFS-on-ext3 has been publicly tested at a bigger scale than any other underlying
  === XFS ===

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