zero size file after power failure with kernel 2.6.30.5

[Eric Sandeen]

Michael Monnerie wrote:
> I have /home mounted like this:
> /dev/sda3 on /disks/work1 type xfs 
> (rw,noatime,logbufs=8,logbsize=256k,attr2,barrier,largeio,swalloc)
> 
> Hardware: onboard SATA with a single WD VelociRaptor drive.
> 
> My power supply melted and so I had a power fail and a sudden death 
> crash.
> ( So please remember: even when you have a UPS, your power can fail ! )
> 
> After replacing the part, I had almost no isse with my KDE desktop. In 
> earlier XFS releases, I constantly lost several config files all 
> truncated to 0 length or at some point only contained NULLs on such 
> occasions. So the situation improved a lot.
> 
> But almost is not good enough: Exactly my kmail config file was 0 sized 
> - obviously: at least when I started kmail, it started fresh without any 
> accounts or config, but once I exited kmail the config was created with 
> the default values and about 12KB size, while my config has >200KB.
> 
> Shouldn't it be that this doesn't happen anymore? I'd love to be in a 
> position where I really can rely on a crash not trashing any of my files 
> anymore. I used to have reiserfs previously, and never, not a single 
> time despite many crashes, did I have such an issue. I'd really be 
> pleased so see such stability in XFS. I'm using barriers - what else 
> must I do?
> 
> mfg zmi

this will depend on what kde is doing internally as well.

No filesystem can magically protect against buffered data loss on a 
crash.  An application could certainly be doing something that results 
in this sort of thing.  w/o reading some kde code I can't say for sure, 
and I don't mean to blame KDE, but this isn't necessarily a bug in xfs.

-Eric