files/directory limit?

[Todd H.]

Is there a limit on the number of files that can be in a directory in
AIX? If so, what is it? For bonus points, if anyone can point to
where they document such goodies, I'd be most appreciative.

--
Todd H.
[url]http://www.toddh.net/[/url]

[Nicholas Dronen]

Todd H. <comphelp@toddh.net> wrote:

TH> Is there a limit on the number of files that can be in a directory in
TH> AIX? If so, what is it? For bonus points, if anyone can point to
TH> where they document such goodies, I'd be most appreciative.

Since a directory is just a file with a certain bit set in its inode,
and with directory names and inodes stored in it as a table, I believe
the only limit on the number of directory entries is the limit on the
side of a file. May be wrong.

The real downside to having lots and lots of files in a directory is
the long time it takes to find files. A directory in JFS is nothing
but a stream of name/inode records. In JFS2, it's a b-tree, which
makes look-ups much faster.

Whether you use JFS or JFS2, it's generally poor style not to partition
a large directory into a number of smaller subdirectories.

Regards,

Nicholas

--
"Why shouldn't I top-post?" [url]http://www.aglami.com/tpfaq.html[/url]
"Meanings are another story." [url]http://www.ifas.org/wa/glossolalia.html[/url]

[The Swordsman]

Am 15 Sep 2003 23:24:22 GMT hat Nicholas Dronen <ndronen@io.frii.com>
geschrieben:

> Todd H. <comphelp@toddh.net> wrote:
>
> TH> Is there a limit on the number of files that can be in a directory in
> TH> AIX? If so, what is it? For bonus points, if anyone can point to
> TH> where they document such goodies, I'd be most appreciative.
>
> Since a directory is just a file with a certain bit set in its inode,
> and with directory names and inodes stored in it as a table, I believe
> the only limit on the number of directory entries is the limit on the
> side of a file. May be wrong.
>
> The real downside to having lots and lots of files in a directory is
> the long time it takes to find files. A directory in JFS is nothing
> but a stream of name/inode records. In JFS2, it's a b-tree, which
> makes look-ups much faster.
>
> Whether you use JFS or JFS2, it's generally poor style not to partition
> a large directory into a number of smaller subdirectories.
>
> Regards,
>
> Nicholas
>

Generally spoken, I agree with Nicolas' statement regarding poor style, but
sometimes that application is forcing us to use many files in a single
directory. The problems start when using simple commands like ls *.nsf with
the shell expanding *.nsf. Beyond a certain number of files, the input lis
for ls will become too large. You need to work with e.g. find than.

We are currently using directories with +2000 files.

Regards,

Jörg

[Todd H.]

The Swordsman <the_swordsman@web.de> writes:

> Am 15 Sep 2003 23:24:22 GMT hat Nicholas Dronen <ndronen@io.frii.com>
> geschrieben:
>

> > Todd H. <comphelp@toddh.net> wrote:
> >
> > TH> Is there a limit on the number of files that can be in a
> > TH> directory in AIX? If so, what is it? For bonus points, if
> > TH> anyone can point to where they document such goodies, I'd be
> > TH> most appreciative.
> >
> > The real downside to having lots and lots of files in a directory is
> > the long time it takes to find files. A directory in JFS is nothing
> > but a stream of name/inode records. In JFS2, it's a b-tree, which
> > makes look-ups much faster.

>
> Generally spoken, I agree with Nicolas' statement regarding poor
> style, but sometimes that application is forcing us to use many files
> in a single directory.

Yes. That is the case that has me asking the question. :-)

> We are currently using directories with +2000 files.

That's helpful to know thanks!

Best Regards,
--
Todd H.
[url]http://www.toddh.net/[/url]

[M. Bouherrou]

Just an addition, you have to know that within a filesystem the number of
inodes is limited (each file/directory use an inode), so you may run out
of inodes if too much files are stored. But not worry you can tune the FS to
add inodes as needed.

"Todd H." <comphelp@toddh.net> a écrit dans le message de news:
[email]m04qzcu4ae.fsf@rcn.com[/email]...

> The Swordsman <the_swordsman@web.de> writes:

> > Am 15 Sep 2003 23:24:22 GMT hat Nicholas Dronen <ndronen@io.frii.com>
> > geschrieben:
> >

> > > Todd H. <comphelp@toddh.net> wrote:
> > >
> > > TH> Is there a limit on the number of files that can be in a
> > > TH> directory in AIX? If so, what is it? For bonus points, if
> > > TH> anyone can point to where they document such goodies, I'd be
> > > TH> most appreciative.
> > >
> > > The real downside to having lots and lots of files in a directory is
> > > the long time it takes to find files. A directory in JFS is nothing
> > > but a stream of name/inode records. In JFS2, it's a b-tree, which
> > > makes look-ups much faster.

> >
> > Generally spoken, I agree with Nicolas' statement regarding poor
> > style, but sometimes that application is forcing us to use many files
> > in a single directory.

>
> Yes. That is the case that has me asking the question. :-)
>

> > We are currently using directories with +2000 files.

>
> That's helpful to know thanks!
>
> Best Regards,
> --
> Todd H.
> [url]http://www.toddh.net/[/url]