From: Pavel Machek <pavel@ucw.cz>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: bhalevy@panasas.com, arjan@infradead.org,
mikulas@artax.karlin.mff.cuni.cz, jaharkes@cs.cmu.edu,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
nfsv4@ietf.org
Subject: Re: Finding hardlinks
Date: Tue, 2 Jan 2007 19:15:05 +0000 [thread overview]
Message-ID: <20070102191504.GA5276@ucw.cz> (raw)
In-Reply-To: <E1H01Og-0007TF-00@dorka.pomaz.szeredi.hu>
Hi!
> > >> It seems like the posix idea of unique <st_dev, st_ino> doesn't
> > >> hold water for modern file systems
> > >
> > > are you really sure?
> >
> > Well Jan's example was of Coda that uses 128-bit internal file ids.
> >
> > > and if so, why don't we fix *THAT* instead
> >
> > Hmm, sometimes you can't fix the world, especially if the filesystem
> > is exported over NFS and has a problem with fitting its file IDs uniquely
> > into a 64-bit identifier.
>
> Note, it's pretty easy to fit _anything_ into a 64-bit identifier with
> the use of a good hash function. The chance of an accidental
> collision is infinitesimally small. For a set of
>
> 100 files: 0.00000000000003%
> 1,000,000 files: 0.000003%
I do not think we want to play with probability like this. I mean...
imagine 4G files, 1KB each. That's 4TB disk space, not _completely_
unreasonable, and collision probability is going to be ~100% due to
birthday paradox.
You'll still want to back up your 4TB server...
Pavel
--
Thanks for all the (sleeping) penguins.
next prev parent reply other threads:[~2007-01-02 19:35 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-20 9:03 Finding hardlinks Mikulas Patocka
2006-12-20 11:44 ` Miklos Szeredi
2006-12-20 16:36 ` Mikulas Patocka
2006-12-20 16:50 ` Miklos Szeredi
2006-12-20 19:54 ` Al Viro
2006-12-20 20:12 ` Mikulas Patocka
2006-12-31 15:02 ` Mikulas Patocka
2006-12-21 18:58 ` Jan Harkes
2006-12-21 23:49 ` Mikulas Patocka
2006-12-22 5:05 ` Jan Harkes
2006-12-23 10:18 ` Arjan van de Ven
2006-12-23 14:00 ` Mikulas Patocka
2006-12-28 9:06 ` Benny Halevy
2006-12-28 9:06 ` Benny Halevy
2006-12-28 10:05 ` Arjan van de Ven
2006-12-28 15:24 ` Benny Halevy
2006-12-28 15:24 ` Benny Halevy
2006-12-28 19:58 ` Miklos Szeredi
2006-12-29 0:51 ` Bryan Henderson
2007-01-02 19:15 ` Pavel Machek [this message]
2007-01-02 20:41 ` Miklos Szeredi
2007-01-02 20:50 ` Mikulas Patocka
2007-01-02 21:10 ` Miklos Szeredi
2007-01-02 21:37 ` Mikulas Patocka
2007-01-03 11:56 ` Pavel Machek
2007-01-03 12:33 ` Miklos Szeredi
2007-01-03 12:42 ` Pavel Machek
2007-01-11 23:43 ` Denis Vlasenko
2007-01-03 12:45 ` Martin Mares
2007-01-03 13:54 ` Matthew Wilcox
2007-01-03 15:51 ` Miklos Szeredi
2007-01-03 19:04 ` Mikulas Patocka
2007-01-04 22:59 ` Pavel Machek
2007-01-05 8:43 ` Miklos Szeredi
2007-01-05 13:12 ` Pavel Machek
2007-01-05 13:55 ` Miklos Szeredi
2007-01-05 14:08 ` Mikulas Patocka
2007-01-05 15:09 ` Miklos Szeredi
2007-01-05 15:15 ` Miklos Szeredi
2007-01-08 11:27 ` Pavel Machek
2007-01-08 5:57 ` Mikulas Patocka
2007-01-08 8:49 ` Miklos Szeredi
2007-01-08 11:29 ` Pavel Machek
2007-01-08 12:00 ` Miklos Szeredi
2007-01-08 13:26 ` Martin Mares
2007-01-08 13:39 ` Miklos Szeredi
2007-01-09 16:26 ` Steven Rostedt
2007-01-09 19:53 ` Frank van Maarseveen
2007-01-09 20:11 ` Steven Rostedt
2007-01-11 10:07 ` Pádraig Brady
2007-01-11 10:07 ` Pádraig Brady
2007-01-09 23:43 ` Bryan Henderson
2007-01-09 23:46 ` Pavel Machek
2007-01-10 0:02 ` Matthew Wilcox
2007-01-10 17:30 ` Bryan Henderson
2007-01-10 17:38 ` Symbolic links vs hard links Bryan Henderson
2007-01-10 17:42 ` Matthew Wilcox
2007-01-11 20:03 ` Bryan Henderson
2007-01-10 19:33 ` Mikulas Patocka
2007-01-10 1:30 ` Finding hardlinks Steven Rostedt
2007-01-05 17:30 ` Frank van Maarseveen
2006-12-28 18:14 ` Mikulas Patocka
2006-12-29 10:34 ` Trond Myklebust
2006-12-29 10:34 ` Trond Myklebust
2006-12-30 1:04 ` Mikulas Patocka
2007-01-01 2:30 ` Nikita Danilov
2007-01-01 22:58 ` Mikulas Patocka
2007-01-01 23:05 ` Nikita Danilov
2007-01-01 23:22 ` Mikulas Patocka
2007-01-04 13:59 ` Nikita Danilov
2007-01-02 23:14 ` Trond Myklebust
2007-01-02 23:50 ` Mikulas Patocka
2006-12-28 13:22 ` Jeff Layton
2006-12-28 15:12 ` Benny Halevy
2006-12-28 15:12 ` Benny Halevy
2006-12-28 15:54 ` Jeff Layton
2006-12-28 16:26 ` Jan Engelhardt
2006-12-28 18:15 ` Bryan Henderson
2006-12-28 18:43 ` Arjan van de Ven
2006-12-29 0:44 ` Bryan Henderson
2006-12-29 3:03 ` Phillip Lougher
2006-12-29 8:41 ` Arjan van de Ven
2006-12-29 15:12 ` Phillip Lougher
2006-12-29 15:43 ` Arjan van de Ven
2006-12-29 8:36 ` Arjan van de Ven
2006-12-29 18:08 ` Bryan Henderson
2006-12-29 18:18 ` Arjan van de Ven
2006-12-29 21:36 ` Bryan Henderson
2006-12-29 22:36 ` Arjan van de Ven
2006-12-28 18:17 ` Mikulas Patocka
2006-12-28 20:07 ` Halevy, Benny
2006-12-28 20:07 ` Halevy, Benny
2006-12-29 10:28 ` [nfsv4] " Trond Myklebust
2006-12-31 21:25 ` Halevy, Benny
2006-12-31 21:25 ` Halevy, Benny
2007-01-02 23:21 ` [nfsv4] " Trond Myklebust
2007-01-02 23:21 ` Trond Myklebust
2007-01-03 12:35 ` [nfsv4] " Benny Halevy
2007-01-03 12:35 ` Benny Halevy
2007-01-04 0:43 ` [nfsv4] " Trond Myklebust
2007-01-04 8:36 ` Trond Myklebust
2007-01-04 10:04 ` Benny Halevy
2007-01-04 10:04 ` Benny Halevy
2007-01-04 10:47 ` [nfsv4] " Trond Myklebust
2007-01-04 18:12 ` Bryan Henderson
2007-01-04 18:26 ` Peter Staubach
2007-01-05 8:28 ` Benny Halevy
2007-01-05 10:29 ` Trond Myklebust
2007-01-05 16:40 ` Nicolas Williams
2007-01-05 16:56 ` Trond Myklebust
2007-01-06 7:44 ` Halevy, Benny
2007-01-10 13:04 ` Benny Halevy
2006-12-29 10:12 ` Trond Myklebust
2006-12-31 21:19 ` Halevy, Benny
2007-01-02 23:20 ` Trond Myklebust
2007-01-02 23:46 ` Trond Myklebust
2006-12-28 17:58 ` Bryan Henderson
2006-12-28 18:13 ` Shaya Potter
2006-12-28 22:50 ` Halevy, Benny
2007-01-11 23:35 ` Denis Vlasenko
2006-12-29 10:02 ` Pavel Machek
2007-01-01 22:47 ` Mikulas Patocka
2007-01-01 23:53 ` Jan Harkes
2007-01-02 0:04 ` Mikulas Patocka
2007-01-03 18:58 ` Frank van Maarseveen
2007-01-03 19:17 ` Mikulas Patocka
2007-01-03 19:26 ` Frank van Maarseveen
2007-01-03 19:31 ` Mikulas Patocka
2007-01-03 20:26 ` Frank van Maarseveen
2007-01-12 0:00 ` Denis Vlasenko
2007-01-03 22:30 ` Pavel Machek
2007-01-03 21:09 ` Bryan Henderson
2007-01-03 22:01 ` Frank van Maarseveen
2007-01-03 23:43 ` Mikulas Patocka
2007-01-04 0:12 ` Frank van Maarseveen
2007-01-08 6:19 ` Mikulas Patocka
[not found] <7x5mR-2wX-3@gated-at.bofh.it>
[not found] ` <7x9Ad-18O-35@gated-at.bofh.it>
[not found] ` <7yXEy-UI-39@gated-at.bofh.it>
[not found] ` <7yYKa-2Ds-3@gated-at.bofh.it>
[not found] ` <7zcWP-7ET-5@gated-at.bofh.it>
[not found] ` <7zdzA-jc-27@gated-at.bofh.it>
[not found] ` <7zeP5-2ic-15@gated-at.bofh.it>
[not found] ` <7zgH9-5my-17@gated-at.bofh.it>
[not found] ` <7zJSM-14t-9@gated-at.bofh.it>
[not found] ` <7zSW5-6cj-9@gated-at.bofh.it>
[not found] ` <7zX9l-4rS-7@gated-at.bofh.it>
[not found] ` <7zXMb-5g5-27@gated-at.bofh.it>
2007-01-05 23:54 ` Bodo Eggert
2007-01-05 23:54 ` Bodo Eggert
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