On Mon, Feb 11, 2008 at 05:46:29PM +0100, Felix E. Klee wrote:
> I heard that, in case of a power failure, XFS may lose data, even data
> that was already existing on the disk. For example, I heard horror
> stories of files being overwritten with zeros.
>
> Are those stories true?
>
> If so:
>
> * Do you recommend not using XFS on devices that may frequently fail due
> to power failure?
Depends on how much you care about your system and data.
I use XFS on write-cache enabled SATA drives without barriers with
no UPS (yes, it's unsafe!) and I lose power at least once a week. I
haven't had a data loss or corruption in over two years and tens of
power failures....
> * Is it possible to find out what files have been damaged?
Not easily.
> If not,
> will only files be affected that have been changed during the last
> couple of hours?
Last few seconds before the power fail, actually.
> * Are there options to increase data safety? Should one run a regular
> "sync" in a cron job?
If you are truly paranoid - turn off drive caching and mount with
the 'wsync' option.
> * Is it unsafe to use XFS in a virtual machine which may sometimes be
> terminated without proper shutdown?
I do that all the time, too. Corruption is rare and usually
as a result of some bug in the code I'm testing ;)
> I currently am using XFS under Ubuntu 7.10 (Kernel 2.6.22), running in a
> virtual machine (VMware) under Windows. The XFS file system is in a
> native partition on a second HDD.
Should be just fine. If you are really concerned - test it.
Cheers,
Dave.
>
> --
> Felix E. Klee
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>
--
Dave Chinner
Principal Engineer
SGI Australian Software Group
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