[svn.haxx.se] · SVN Dev · SVN Users · SVN Org · TSVN Dev · TSVN Users · Subclipse Dev · Subclipse Users · this month's index

Re: FSFS packing functionally complete

From: Branko Čibej <brane_at_xbc.nu>
Date: Sat, 29 Nov 2008 02:32:36 +0100

Mark Mielke wrote:
> Branko Čibej wrote:
>> Mark Mielke wrote:
>>> Hyrum K. Wright wrote:
>>>> The basic benefit is the elimination of what I term "the inode
>>>> problem" Any
>>>> file on disk is physically stored on a set of sectors, which are of
>>>> fixed size.
>>>> It depends on the file system, but most sectors can not store parts
>>>> of multiple
>>>> files. *Every* file requires at least one sector, so if a file only
>>>> contains 1
>>>> byte of actual data, it still reserves an entire sector on disk
>>>> (though again
>>>> this varies by file system). The size of a sector may range from 512
>>>> bytes to
>>>> 32 kB or more. IIRC, ext3 uses 4 kB sectors.
>>> The inode problem is a different problem - each file system often has
>>> inode slots allocated up front, and if they become exhausted, no new
>>> files can be created, even if the disk isn't fully in use.
>> Nah, that's just stupid ancient file systems; hardly better than the
>> ancient 14-character filename length limit. XFS and a few others on
>> Unix, NTFS, HFS+ and the like don't have that problem.
>> You can bet that anyone who has a really big repository isn't hosting it
>> on ext2 these days; Or as least if they do, it's some sysadmins should
>> be shot.
>> Block size overhead and directory sizes are the real issue here.
> You sure you aren't making things up? :-) What's wrong with ext3? I
> would bet ext3 is the most common in use for Linux platforms, and ext3
> has inode limits. All file systems I can think of reserve
> administration space for tracking purposes, and once the space is
> exhausted, problems occur.

ext2, ext3 .... same difference. It's a beefed up patchwork of new
features on top of an ancient filesystem that's outlived its usefulness
given how large volumes tend to be these days. I'd never use it on a
production server, either for databases or Subversion repositories.

The fact that it's the default on many Linux distros is just
unfortunate, though I'll agree it's adequate for your basic desktop
environment. I'm pretty sure that an admin who wants to set up a
repository that's big enough that I-node limits could be a problem will
either not use ext3, or not earn her salary. :)

(FWIW, I'm using XFS on / on my Ubuntu laptop, it's faster and uses less
overhead than ext3. But I'm sure that's just a personal quirk; I have a
patched kernel, too. :) )

-- Brane

To unsubscribe, e-mail: dev-unsubscribe_at_subversion.tigris.org
For additional commands, e-mail: dev-help_at_subversion.tigris.org
Received on 2008-11-29 02:33:26 CET

This is an archived mail posted to the Subversion Dev mailing list.

This site is subject to the Apache Privacy Policy and the Apache Public Forum Archive Policy.