Pacman fragmentation

Komodo · 2005-12-29 21:51:28

Here are a few questions about pacman fragmentation - I've been using Arch for about a year now (my 'joined on Nov 03' is cos I got my name changed ), and feel that it's time I should concern myself with this.

:?: What's the command to defragment?

:?: When people refer to 'pacman fragmentation', what exactly do they mean? Fragmentation of pacman's files on disk?

:?: Why is it a problem? I thought defragmentation became obsolete in recent years, due to hard drive speeds increasing so dramatically?

Gullible Jones · 2005-12-29 22:20:40

1. pacman-optimize

2. They're referring to the spreading of the /var/lib/pacman directory across the disk, making access slower. Actual external fragmentation of files in /var/lib/pacman is very unlikely, given the nature of Linux filesystems.

3. Do an installation on a big FAT32 partition and tell me fragmentation is no longer a problem.

phrakture · 2005-12-29 22:52:09

Komodo wrote:

Why is it a problem? I thought defragmentation became obsolete in recent years, due to hard drive speeds increasing so dramatically?

Fragmentation of individual files is not a problem - the problem is that the pacman "database" consists of many many small files, which "fragment" - the term "fragmentation" when talking about the pacman database is a misnomer - it's not the same as disk fragmentation.

Komodo · 2005-12-29 23:05:24

phrakture wrote:

the term "fragmentation" when talking about the pacman database is a misnomer - it's not the same as disk fragmentation.

That makes more sense to me phrakture, thanks.

GJ, I've always found it hard to believe that fragmentation wasn't a problem, but I'm (fortunate enough to be) taught by the leaders in the computer science field in the UK, and they all reckon it's no longer an issue...

Gullible Jones · 2005-12-29 23:32:01

It's not much of an issue any more, but that's because of filesystem advances for the most part. Even on on Windows, NTFS makes fragmentation much less of and issue.

(There are some exceptions... Under certain conditions, XFS can get very fragmented, and ReiserFS can suffer some minor external fragmentation if you use tail packing. Also, Reiser4, wonder of wonders, seems to have a notable propensity for fragmenting.)

iBertus · 2005-12-30 04:59:06

I feel that fragmentation will always be an issue given time and usage. You just can't ensure that data will always be written in any certain order and thus cannot be certain fragmentation will not occur.

I personally only worry about it in directories containing large numbers of files or large datasets that take ages to work with anyway. Maybe I'll quit caring about it when I can afford to upgrade to the newest, greatest hard disc technology (still using plain-ole IDE).

phrakture · 2005-12-30 16:19:07

As for ext filesystems, disc fragmentation should be at a constant 5-10%, that's just part of the way it works... there will always be some fragmentation. However, the way ext works, the fragmentation doesn't affect the performance of the filesystem.

That said, the only time ext becomes bogged down due to fragmentation is when the filesystem is like 95% full, and you're constantly deleting and adding a decent percentage of the total space... this tends to happen on some high-usage production servers every so often.

Komodo · 2005-12-30 16:37:18

phrakture wrote:

the only time ext becomes bogged down due to fragmentation is when the filesystem is like 95% full, and you're constantly deleting and adding a decent percentage of the total space... this tends to happen on some high-usage production servers every so often.

hmm, ok. I wish there was a decent resource for random hardware info like that; software info is abundant, but not detailed hardware info like that (ok, so I guess it's technically a software issue, but you know what i mean, i hope )

phrakture · 2005-12-30 16:58:41

Komodo wrote:

hmm, ok. I wish there was a decent resource for random hardware info like that

Try these... google found 'em:
http://web.mit.edu/tytso/www/linux/ext2intro.html
http://uranus.it.swin.edu.au/~jn/explore2fs/es2fs.htm

Komodo · 2005-12-30 17:05:19

phrakture wrote:

Komodo wrote:
hmm, ok. I wish there was a decent resource for random hardware info like that
Try these... google found 'em

Heh, appreciated phrakture, but I know how to use google. What I meant is, there doesn't seem to be a resource that's an amalgamation of useful hardware/low-level software info.

Arch Linux

#1 2005-12-29 21:51:28

Pacman fragmentation

#2 2005-12-29 22:20:40

Re: Pacman fragmentation

#3 2005-12-29 22:52:09

Re: Pacman fragmentation

#4 2005-12-29 23:05:24

Re: Pacman fragmentation

#5 2005-12-29 23:32:01

Re: Pacman fragmentation

#6 2005-12-30 04:59:06

Re: Pacman fragmentation

#7 2005-12-30 16:19:07

Re: Pacman fragmentation

#8 2005-12-30 16:37:18

Re: Pacman fragmentation

#9 2005-12-30 16:58:41

Re: Pacman fragmentation

#10 2005-12-30 17:05:19

Re: Pacman fragmentation

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