Mailinglist Archive: opensuse (3513 mails)

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Re: [opensuse] openSUSE 11.1 x86_64 on a 512MB RAM system
  • From: Rui Santos <rsantos@xxxxxxxxxxxxx>
  • Date: Tue, 06 Jan 2009 13:47:02 +0000
  • Message-id: <496360D6.5000202@xxxxxxxxxxxxx>
Carlos E. R. wrote:


On Tuesday, 2009-01-06 at 11:16 -0000, Rui Santos wrote:

I've stumbled on a problem, on a test machine, using openSUSE 11.1
x86_64 system with 512MB of RAM. This test was just to confirm a friends
claim that he was unable to get a working server with that kind of
hardware.

The problem is that openSUSE uses all of the memory for simple
tasks, like fsck. Just as an example, here is an strace of a fsck.vfat
on a filesystem. For this I just left the system with 90MB free memory
before I ran this command:

2090 execve("/sbin/fsck.vfat", ["fsck.vfat", "/dev/sdb1"], [/* 20 vars
*/]) = 0

...

2090 lseek(3, 39069696, SEEK_SET) = 39069696
2090 read(3, <unfinished ...>
2090 +++ killed by SIGKILL +++

:-)



The latest SIGKILL was generated by ooom-kill. Linux kernel kills
the process in order to get memory.
There were no programs running, as this command was issued under
init 1
The system has no SWAP

It is known.

If you check up the fsck script run at boot, you will see that it
activates swap before running the fsck. You need swap with so "little"
memory. Linux is memory hungry, and some programs even more so.

Look, /etc/init.d/boot.rootfsck:

start)
#
# fsck may need a huge amount of memory, so make sure, it is
there.
#
echo "Activating swap-devices in /etc/fstab..."
swapon -ae &> /dev/null
rc_status -v1 -r

See the comment?


And with 64bits, it is worse. Just consider, that a program assigns a
long int... if it was 32 bits, now it is double that, 64 bits. If the
programmers are not carefull, compiling for 64 bits might end with
using double memory }:-)

So... you're saying that the problem may be that some programs may be
more memory hungry than others, witch can have worst results on a 64
bits OS. So this mau be a general Linux issue, and not openSUSE specific.
Man, It never crossed my mind I would need 512MB of RAM to perform a
file system check on a 850MB worth of files on a 100GB vfat file system.
Gee, this is really, really scary...

Thanks for your reply Carlos,


-- Cheers,
Carlos E. R.

--
Rui Santos
http://www.ruisantos.com/

Veni, vidi, Linux!

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