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| author | Jan Kara <jack@suse.cz> | 2019-12-18 12:12:10 +0100 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-12-21 21:36:53 -0500 |
| commit | 23f6b02405343103791c6a9533d73716cdf0c672 (patch) | |
| tree | 9e36dfd15bf7dae9e019ab43b3e6b866e59134e5 /Documentation | |
| parent | 68d7b2d838f1aff4d46a793a2fae33e8ad19223e (diff) | |
| download | lwn-23f6b02405343103791c6a9533d73716cdf0c672.tar.gz lwn-23f6b02405343103791c6a9533d73716cdf0c672.zip | |
ext4: clarify impact of 'commit' mount option
The description of 'commit' mount option dates back to ext3 times.
Update the description to match current meaning for ext4.
Reported-by: Paul Richards <paul.richards@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191218111210.14161-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/ext4.rst | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst index 059ddcbe769d..9bc93f0ce0c9 100644 --- a/Documentation/admin-guide/ext4.rst +++ b/Documentation/admin-guide/ext4.rst @@ -181,14 +181,17 @@ When mounting an ext4 filesystem, the following option are accepted: system after its metadata has been committed to the journal. commit=nrsec (*) - Ext4 can be told to sync all its data and metadata every 'nrsec' - seconds. The default value is 5 seconds. This means that if you lose - your power, you will lose as much as the latest 5 seconds of work (your - filesystem will not be damaged though, thanks to the journaling). This - default value (or any low value) will hurt performance, but it's good - for data-safety. Setting it to 0 will have the same effect as leaving - it at the default (5 seconds). Setting it to very large values will - improve performance. + This setting limits the maximum age of the running transaction to + 'nrsec' seconds. The default value is 5 seconds. This means that if + you lose your power, you will lose as much as the latest 5 seconds of + metadata changes (your filesystem will not be damaged though, thanks + to the journaling). This default value (or any low value) will hurt + performance, but it's good for data-safety. Setting it to 0 will have + the same effect as leaving it at the default (5 seconds). Setting it + to very large values will improve performance. Note that due to + delayed allocation even older data can be lost on power failure since + writeback of those data begins only after time set in + /proc/sys/vm/dirty_expire_centisecs. barrier=<0|1(*)>, barrier(*), nobarrier This enables/disables the use of write barriers in the jbd code. |