[OpenAFS] generating a listing of Mount points

[Nathan Neulinger]

Phil.Moore@morganstanley.com wrote:
> 
> >>>>> "Derek" == Derek Atkins <warlord@MIT.EDU> writes:
> 
> Derek> You can always do something like:
> Derek> find /afs/<your cell> -type d -print | xargs fs lsm | grep -v "not a mount point"
> 
> You have GOT to be kidding...
> 
> For any AFS cell of any reasonable size, you're going to run into the
> length limit for command line arguments in most shells on most systems
> when xargs tries to pass a bajillion directories to fs.

If that happens - the xargs you are using is broken. Xargs is supposed
to pass at most up to the max cmd line length. 

Worst case scenario - just add "-n maxfiles" where X is how many files
to list or "-s maxchars". 

> That simply does NOT scale.
> 
> Now, this happens to be on my list of management tools needed for AFS,
> namely a mount point database.  The missing peice isn't the code to
> scan the salvager output (that's very simple), but some changes needed
> to the salvager itself.
> 
> Since a full salvage requires taking the fileserver down, we need to
> be able to run the salvager in a passive query mode, where volumes are
> opened read-only, scanned for mount points (or perhaps other
> aberrations), and the resulted reported in the salvager logs.  Then,
> it would be straight forward to write code that audits the mount
> points in an entire AFS cell by salvaging (passively) each fileserver,
> collecting the logs, and analyzing them centrally.
> 
> The design I have would do this incrementally, and only scan
> individual volumes, which LastUpdate timestamp has changed, making it
> cheap to keep this uptodate.

I thought that the showmounts stuff already did read-only? And salvaging
the backup volume (can you do that?) would eliminate any negatives to
running the salvager.

> You can then analyze this database for mount point loops, fiund
> unmounted volume heirarchies, multiply mounted heirarchies, and all
> kinds of other interesting things, too.
> 
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Nathan Neulinger                       EMail:  nneul@umr.edu
University of Missouri - Rolla         Phone: (573) 341-4841
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