High-sensitivity fs checker (not repairer) for btrfs

2012-11-10 Thread Bob Marley

Hello all
I would like to know if there exists a tool to check the btrfs 
filesystem very thoroughly.

It's ok if it needs the FS unmounted to operate. Also mounted is OK.
It does not need repair capability
It needs very good checking capability: it has to return Good / Bad 
status with the Bad meaning that there is at least ONE inconsistency. 
Good means that it is really really 100% consistent.


Does something like this exists?

We need to detect as much ahead of time as possible if the btrfs 
filesystem has become even just a little bit inconsistent


Thank you
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Re: High-sensitivity fs checker (not repairer) for btrfs

2012-11-10 Thread Hugo Mills
On Sat, Nov 10, 2012 at 10:18:42PM +0100, Bob Marley wrote:
 Hello all
 I would like to know if there exists a tool to check the btrfs
 filesystem very thoroughly.
 It's ok if it needs the FS unmounted to operate. Also mounted is OK.
 It does not need repair capability
 It needs very good checking capability: it has to return Good / Bad
 status with the Bad meaning that there is at least ONE
 inconsistency. Good means that it is really really 100% consistent.
 
 Does something like this exists?
 
 We need to detect as much ahead of time as possible if the btrfs
 filesystem has become even just a little bit inconsistent

   The closest thing is btrfsck. That's about as picky as we've got to
date.

   What exactly is your use-case for this requirement?

   Hugo.

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Re: High-sensitivity fs checker (not repairer) for btrfs

2012-11-10 Thread Bob Marley

On 11/10/12 22:23, Hugo Mills wrote:

The closest thing is btrfsck. That's about as picky as we've got to
date.

What exactly is your use-case for this requirement?


We need a decently-available system. We can rollback filesystem to 
last-known-good if the test detects an inconsistency on current btrfs 
filesystem, but we need a very good test for that (i.e. if 
last-known-good is actually bad we get into serious troubles).


So do you think btrfsck can return a false OK result? can it not-see 
an inconsistency?


Thank you
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Re: High-sensitivity fs checker (not repairer) for btrfs

2012-11-10 Thread cwillu
On Sat, Nov 10, 2012 at 4:32 PM, Bob Marley bobmar...@shiftmail.org wrote:
 On 11/10/12 22:23, Hugo Mills wrote:

 The closest thing is btrfsck. That's about as picky as we've got to
 date.

 What exactly is your use-case for this requirement?


 We need a decently-available system. We can rollback filesystem to
 last-known-good if the test detects an inconsistency on current btrfs
 filesystem, but we need a very good test for that (i.e. if last-known-good
 is actually bad we get into serious troubles).

Scrub is probably more useful as a check, combined with does the
filesystem actually mount.

 So do you think btrfsck can return a false OK result? can it not-see an
 inconsistency?

No set of checks will ever be perfect, so yes.
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