Comment 0 for bug 1097042
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| lemonsqueeze (lemonsqueeze) wrote by default ext3 is mounted without barrier=1 in lucid | #0 |
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35a32c5
(Get the code!)
On my system, a default ext3 mount (no fstab entry) results in:
$ cat /proc/mounts
/dev/sda6 /media/space ext3 rw,nosuid,
We can see the "barrier=1" option is missing by default, which can cause severe filesystem corruption in case of power failure (i've been hit recently). Quoting mount(1):
"barrier=0 / barrier=1
This enables/disables barriers. barrier=0 disables it, barrier=1 enables it. Write barriers enforce proper
on-disk ordering of journal commits, making volatile disk write caches safe to use, at some performance
penalty. The ext3 filesystem does not enable write barriers by default. Be sure to enable barriers unless
your disks are battery-backed one way or another. Otherwise you risk filesystem corruption in case of power
failure."
the issue is fixed in later kernels (precise 3.2.0-35 is not affected), but lucid users are left to suffer the consequences of this horrifying default.
$ uname -a
Linux netbook 2.6.32-45-generic #101-Ubuntu SMP Mon Dec 3 15:41:13 UTC 2012 i686 GNU/Linux