Public bug reported:
On my system, a default ext3 mount (no fstab entry) results in:
$ cat /proc/mounts
/dev/sda6 /media/space ext3
rw,nosuid,nodev,relatime,errors=continue,user_xattr,acl,data=ordered 0 0
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
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: i386 lucid
** Attachment added: "lsb_release.txt"
https://bugs.launchpad.net/bugs/1097042/+attachment/3476349/+files/lsb_release.txt
** Information type changed from Private Security to Public
** Description changed:
On my system, a default ext3 mount (no fstab entry) results in:
$ cat /proc/mounts
/dev/sda6 /media/space ext3
rw,nosuid,nodev,relatime,errors=continue,user_xattr,acl,data=ordered 0 0
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."
+ 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
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https://bugs.launchpad.net/bugs/1097042
Title:
by default ext3 is mounted without barrier=1 in lucid
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