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| author | Eric Sandeen <sandeen@redhat.com> | 2008-05-26 12:29:46 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2008-05-26 12:29:46 -0400 |
| commit | 571640cad3fda6475da45d91cf86076f1f86bd9b (patch) | |
| tree | a97ff3da9b60251c68358cd000c217cb37915ea2 /Documentation/filesystems | |
| parent | 034772b068be62a79470d6c1b81b01fbe27793ac (diff) | |
| download | linux-571640cad3fda6475da45d91cf86076f1f86bd9b.tar.gz linux-571640cad3fda6475da45d91cf86076f1f86bd9b.tar.bz2 linux-571640cad3fda6475da45d91cf86076f1f86bd9b.zip | |
ext4: enable barriers by default
I can't think of any valid reason for ext4 to not use barriers when
they are available; I believe this is necessary for filesystem
integrity in the face of a volatile write cache on storage.
An administrator who trusts that the cache is sufficiently battery-
backed (and power supplies are sufficiently redundant, etc...)
can always turn it back off again.
SuSE has carried such a patch for ext3 for quite some time now.
Also document the mount option while we're at it.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/ext4.txt | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 560f88dc7090..0c5086db8352 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -139,8 +139,16 @@ commit=nrsec (*) Ext4 can be told to sync all its data and metadata Setting it to very large values will improve performance. -barrier=1 This enables/disables barriers. barrier=0 disables - it, barrier=1 enables it. +barrier=<0|1(*)> This enables/disables the use of write barriers in + the jbd code. barrier=0 disables, barrier=1 enables. + This also requires an IO stack which can support + barriers, and if jbd gets an error on a barrier + write, it will disable again with a warning. + Write barriers enforce proper on-disk ordering + of journal commits, making volatile disk write caches + safe to use, at some performance penalty. If + your disks are battery-backed in one way or another, + disabling barriers may safely improve performance. orlov (*) This enables the new Orlov block allocator. It is enabled by default. |