Slashdot Mirror

← Back to Stories (view on slashdot.org)

Ext3 Filesystem Explained

Posted by michael on from the journaling-for-fun-and-profit dept.

sheckard writes: "The next installment of the wonderful Advanced filesystem implementor's guide, part 7, details the ext3 filesystem in all of its glory. This is another great voyage into the world of journaling filesystems, and ext3 has been rock-solid in my experience."

6 of 174 comments (clear)

  1. Distro battles? Nah. Journaling fs battles! by Deal-a-Neil · · Score: 5, Informative

    ext3 catches my fancy because there's no ext2 --> ext3 conversion -- you just have to unmount, make a journal file, and remount. reiserfs migration is a challenge for the huge partitions.

  2. Re:Distro battles? Nah. Journaling fs battles! by ThatComputerGuy · · Score: 3, Informative

    And because there's only a journal as an addition, you can remount as ext2 after a clean unmount and everything will still work fine.

    --
    XML is like violence. If it doesn't solve the problem, use more.
  3. Re:Partition resizing? by Sapien__ · · Score: 5, Informative
    This thread might be useful.

    To summarize: yes, it's possible to resize ext3 partitions, so long as your resizer doesn't mind. Don't use Partition Magic to do it. It doesn't like it. Badly.

  4. Re:The journalling filesystem myth by cowbutt · · Score: 5, Informative
    Let's say the journaling file system has 5% overhead (it probably has more). That means you lose more than 1h per day on a busy server--it's spread out, but it's still lost. You'd have to do a lot of rebooting in order to make up for that in terms of "saved" fsck time.

    Actually, Andrew Morton reckons ext3 is actually quicker than ext2 in spite of the journalling. Go figure. :)

    --

  5. Re:The journalling filesystem myth by be-fan · · Score: 3, Informative

    Actually, the new journaling filesystems (ReiserFS, XFS, and JFS) are all *faster* than ext2. Also, journaling itself can cost very little these days because modern JFSs use large buffers and coalesce writes. For example, BFS achieves metadata performance nearly as high as ext2 on a heavily loaded system. So if all you're doing all day is creating/deleting/growing/shrinking files, the filesystem is only slightly slower. When you factor in all the performance improvements, it end up being faster.

    --
    A deep unwavering belief is a sure sign you're missing something...
  6. Re:Performance by rodgerd · · Score: 3, Informative

    IIRC RH7.2 installs ext3 with both data and metadata logging enabled by default, so your performance change is most likely that you're doing two writes for every one you did before.