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Re: want to speed up laptop



Michael Yang wrote:
On Sun, Mar 30, 2008 at 8:26 AM, jeffry s <paragasu@gmail.com> wrote:

I'm using xfce4 now. It seems to me it's also getting slower (been using for
a long time now), I'm wondering if there's any tools to analyze the system
performance?

This might go down poorly with some people... Linux file systems *do* degrade. No war please.

There are several factors which combine to hurt overall disk performance, CPU load, memory bandwidth, disk interface bandwidth and the disk itself. As a result slight changes tend to be magnified in effect. If swap goes on the multi-stream disk use is particularly nasty, and write to disk is slower anyway.

This is likely to go unnoticed on a fast system but laptops particularly have disk poor performance, at root slow platter rotation speed and small diameter. This is basic physics, like for like bit density the bit rate is lower than physically larger disks.

There is no ideal file system, but where there are particular problems consider alternatives to ext3.

Assuming the laptop is reliable, free from system crashes.

Almost by definition a laptop has an inbuilt UPS and therefore power outages should never cause uncontrolled stoppage.

Therefore a non journalled filing system is fairly painless and it might be practical to try one to see how much effect it has.

A very obvious experiment is kill the journal, turning ext3 into ext2, literally ext3 is ext2 plus an extra layer. This is a two way possible operation without touching the basic disk data, with ext2 being upgradable back to ext3 if wanted. (clue in the -j option http://linux.die.net/man/8/tune2fs)

I have done this successfully on a laptop, so I know it is possible, trivially easy, but... there was no critical data on the disk so if it had gone wrong only time was lost. Only one way to discover your mileage.

At least be prepared for handling a non-bootable system and how to get out of it. Debian allows some disk operations during boot with the disk mounted read only.

With ext2 if the system is reset with a mounted disk it will trip a system file check on boot and this is slow, possibly tripping a repair and second boot. Apparently the data safety is the same as ext3, but with the journalling, recovery does not need the detailed file system check after a crash. (anyone here confirm this?)

I could point at instructions but others on list are far more knowledgeable.

There are file system differences and default ext3 fits all has been question some places.
Some numbers and comment, plenty more around the 'net
http://www.debian-administration.org/articles/388

"The first reason is that 'ext3' performance is awesome when the filesystem has just been created and loaded, but degrades very badly over time..."

There are graphs out there showing speed degrade with usage for various file systems.


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