Re: how do versioning filesystems take snapshot of opened files?

["Xin Zhao" <uszhaoxin@gmail.com>]

That's a good point!

But this sounds hopeless to take a real consistent snapshot from app
perspective unless you shutdown the computer. Right?

Thanks.


On 7/3/07, Bryan Henderson <hbryan@us.ibm.com> wrote:
> > Consistent state means many different things.
>
> And, significantly, open/close has nothing to do with any of them
> (assuming we're talking about the system calls).  open/close does not
> identify a transaction; a program may open and close a file multiple times
> the course of making a "single" update.  Also, data and metadata updates
> remain buffered at the kernel level after a close.  And don't forget that
> a single update may span multiple files.
>
> --
> Bryan Henderson                     IBM Almaden Research Center
> San Jose CA                         Filesystems
>
>