[OpenAFS] Re: volume offline due to too low uniquifier (and salvage cannot fix it)

Andrew Deason adeason@sinenomine.net
Tue, 16 Apr 2013 13:37:59 -0500

On Tue, 16 Apr 2013 14:27:12 -0400
Derrick Brashear <shadow@gmail.com> wrote:

> > contents for caching purposes anyway. In option (2) you can have a
> > collision by just removing a file and creating one. Maybe those
> > aren't _so_ different, but that's my impression.
> It's pretty easy to avoid the condition you mention in option 2, but
> it does mean additional "consumption" of the uniq space: on a remove,
> make sure the next uniq we'd allocate is not close to our current
> value, potentially by using a large increment if we are close. But I'm
> not sure it's worth that.

I don't think that really makes it any better. If you increment the
nextuniq to 2000 on a remove, you might have just incremented it to the
same uniq of a file we had 2 deletes ago (or 5, or 3000). It may make it
slightly less likely, but it's just making the number of things that
need to coincidentally happen rise to 3 instead of 2.

Andrew Deason