linux-kernel - Re: the " 'official' point of view" expressed by kernelnewbies.org regarding reiser4 inclusion

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Message-ID: <Pine.LNX.4.63.0607251732001.9159@qynat.qvtvafvgr.pbz>
Date:	Tue, 25 Jul 2006 17:36:12 -0700 (PDT)
From:	David Lang <dlang@...italinsight.com>
To:	David Masover <ninja@...phack.com>
cc:	"Horst H. von Brand" <vonbrand@....utfsm.cl>,
	Mike Benoit <ipso@...ppymail.ca>,
	Matthias Andree <matthias.andree@....de>,
	Hans Reiser <reiser@...esys.com>, lkml@...productions.com,
	Jeff Garzik <jeff@...zik.org>, Theodore Tso <tytso@....edu>,
	LKML <linux-kernel@...r.kernel.org>,
	ReiserFS List <reiserfs-list@...esys.com>
Subject: Re: the " 'official' point of view" expressed by kernelnewbies.org
 regarding reiser4 inclusion

On Tue, 25 Jul 2006, David Masover wrote:

> Horst H. von Brand wrote:
>
>> 18GiB = 18 million KiB, you do have a point there. But 40 million files on
>> that, with some space to spare, just doesn't add up.

if you have 18 million KiB and each file is a single block (512 Bytes = 0.5 Kib) 
then assuming zero overhead you could fit 18 Million KiB / 0.5 KiB = 36 Million 
files on the drive.

thus being scheptical about 40 million files on a 18G drive.

this is only possible if you are abel to have multiple files per 512 byte block.

David Lang

> Right, ok...
>
> Here's a quick check of my box.  I've explicitly stated which root-level
> directories to search, to avoid nfs mounts, chrooted OSes, and virtual
> filesystems like /proc and /sys.
>
> elite ~ # find /bin/ /boot/ /dev/ /emul/ /etc/ /home /lib32 /lib64 /opt
> /root /sbin /tmp /usr /var -type f -size 1 | wc -l
> 246127
>
> According to the "find" manpage:
>
> -size n[bckw]
>      File uses n units of space.  The units are  512-byte  blocks  by
>      default  or  if `b' follows n, bytes if `c' follows n, kilobytes
>      if `k' follows n, or 2-byte words if `w' follows  n.   The  size
>      does  not  count  indirect  blocks,  but it does count blocks in
>      sparse files that are not actually allocated.
>
>
> And I certainly didn't plan it that way.  And this is my desktop box,
> and I'm just one user.  Most of the space is taken up by movies.
>
> And yet, I have almost 250k files at the moment whose size is less than
> 512 bytes.  And this is a normal usage pattern.  It's not hard to
> imagine something prone to creating lots of tiny files, combined with
> thousands of users, easily hitting some 40 mil files -- and since none
> of them are movies, it could fit in 18 gigs.
>
> I mean, just for fun:
>
> elite ~ # find /bin/ /boot/ /dev/ /emul/ /etc/ /home /lib32 /lib64 /opt
> /root /sbin /tmp /usr /var | wc -l
> 866160
>
> It may not be a good idea, but it's possible.  And one of the larger
> reasons it's not a good idea is that most filesystems can't handle it.
> Kind of like how BitTorrent is a very bad idea on dialup, but a very
> good idea on broadband.
>
>
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