Re: Automatic allocation of swap
Osamu Aoki wrote:
On Mon, Aug 02, 2004 at 09:21:05AM +0800, John Summerfield wrote:
Osamu Aoki wrote:
By spreading data over multiple partitions with great gobs of free space
between small (after install) amounts of data, you're forcing longer seeks.
On Sun, Aug 01, 2004 at 09:04:50PM +0800, John Summerfield wrote:
Yes. We all know this. Let's not argue over belief.
If you want us to change something, few ways to do this.
1. clear facts (bench mark result of different configurations)
2. reference some authoritative documents.
and patch always help. Really, I did not say putting swap at the edge
of disk is a good thing. I was annoyed by calling this "stupid".
Please do not call action of DD stupid even if they are.
1. You suppose I'm capable of creating a patch. In fact, my C skills
almost extend far enough that I can read some code.
2. Belief? It seems so obvious to me, it takes me longer to walk across
two streets than it does one.
In the 70s I was a systems programmer on working on IBM mainframes
running OS/VS . One of the tasks we took very seriously was the
minimising of head movement on our disk drives. So far as I know, the
laws of physics that describe their behaviour have not been repealed.
3. I've reread what I said. You misquoted me. I described the RULE OF
THUMB as stupid. I don't believe it originated with the DDs.
However, as a ROT, blind adhearance to ROTs is stupid.
Understand the ROT and you will understand its limitations. I rather
think that ROT was intended to describe an upper limit. Later
interpretations, like intermpretations of Murphy's Law deviate from the
Here is my desktop pc. It's performance sucks bunnies through capilliary
summer@Dolphin:~/d-i$ /sbin/swapon -s
Filename Type Size Used
/var/swapfile file 524280 455604 -1
/var/swapfile2 file 524280 69296 -2
summer@Dolphin:~/d-i$ df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 29G 27G 639M 98% /
no wonder, sigh.
tmpfs 189M 0 189M 0% /dev/shm
/dev/hda1 23M 21M 1.4M 94% /boot
That's almost certainly bad. You probably don't spend much time reading
program files and documentation in comparison with the time reading and
writing variable data.
I have been reading and editing documentation a lot. Please install
debian-reference-en package from Sarge :-) Then you know what.
Oh, please read install guide too. That has good amount of partitioning
Well, I was really referring to your (plural - many DDs) computers.
I agree with that. Breaking the disk into lots of partitions makes it
more likely that one will fill andcause problems. Recently I installed a
server running Sarge and I find / is overfilled to the point I have
problems installing packages:
You're a software developer writing in C? Would you say, less than a
second to read gcc then a minute or so for a compile? Sure, it depends,
but the ratios will be somewhat like those.
I usually do not write C nor compile it much. (With my old 386, I used
to compile my kernel or patched-X for a day, though.)
Really, Linux or Windows, it is bad idea to fill actively used disk up
to 98%. (For your case / partition. /boot may be OK since it is
practically read-only.) For Linux, 90-95%, for windows 60-70% is my
common sense usage.
ns:~# df -t ext3 -m
Filesystem 1M-blocks Used Available Use% Mounted on
/dev2/root2 186 176 1 100% /
/dev/sda1 32 18 13 58% /boot
/dev/sda3 3024 692 2179 25% /usr
/dev/sda4 5378 4714 391 93% /var
/dev/sdb1 17241 12973 3394 80% /home/users
/dev/hda2 37572 28382 7664 79% /mnt/rhl
/dev/hdb2 76905 47356 27987 63%
I don't know why you're telling me Linux is better than Windows. I've
never been a regular Windows user: I used to us OS/2, and before that
MSDOS & DRDOS. (concurrent) CPM/M-86, CP/M, BewdOs80. Not Windows though.
None of these habits should be carried over to Linux and ext2. Linux
native file systems do not need defragmentation under normal use and this
includes any condition with at least 5% of free space on a disk. There is
a defragmentation tool for ext2 called defrag, but users are cautioned
against casual use. ..... From: Linux Partitioning mini-FAQ
You should read that in context. He also makes it clear that's for
everyone. eg VA Linux uses 1x.
He advocates 3x RAM for swap.
Besides that, the implied ording of partitions is wrong. Two or three
swap partitions on one disk makes no sense at all: if Karsten thinks
otherwise, he needs to justify it.
If you think my arguments are wrong, explain why they're wrong.
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