“Nothing determines the peculiar behavior, the feel – even the ultimate success or failure of an operating system – like its virtual memory design.” A must-read article for all the Linux coders regarding the problems of the Linux VM so far and the solutions presented recently. Another good reading regarding VMs is an article about the FreeBSD VM, which is known to be one of the best VMs available.
Regarding the New Linux VM
About The Author
Eugenia Loli
Ex-programmer, ex-editor in chief at OSNews.com, now a visual artist/filmmaker.
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I’ve had a brief sting with FreeBSD 4.4 and I was very impressed with the level of hard disk thrashing (ie. almost non existant). You can immediately tell that FreeBSD has one of the best Virtual Memory / Disk Caching algorithms in the industry. Over the weekend, I installed RedHat 7.2 (2.4.7.11/ext3) and it thrashes the hard disk like mad – obviously the VM/Disk caching isn’t anywhere near as good as FreeBSD.
As a side note, searching for files still takes over a minute of FreeBSD/ext3. Why can’t the *nix world adopt a more database like file system? I miss one second queries from BeOS.
Thank you for your nice comment Zenja.
If you have tried FreeBSD, I am also suggesting to try FreeBSD-CURRENT (which is the beta version that it will become FreeBSD 5.0). FreeBSD (and especially version 5.0) has some impressive features technically-speaking. The only thing that is missing from it, it is indeed a nice and modern filesystem, like SGI’s XFS (which is the one that it is the most similar technically and philosopically to the BeOS’ BFS). I wish that some SGI or BSD engineers make a port or something…
freebsd 4.4/5.0, especailly for 5.0,VM and softupdates enabled ufs filesystem is
much better(speed and stable) than those for linux,my box has mandrake 8.0 and
freebsd 5.0 current installed, i tried them nearly every day. i use reiserFS in
linux,it seems a bit buggy,sometimes works like a monster even crash my box (though few, and i ‘m not sure that’s definitely due to fs).
Linus has released 2.4.14pre6 and he is saying that he thinks the VM is fixed for good…he has 128 MB ram and 1 gig in the swap and no thrashing….he even goes as far to say that he dares people to try and break it…..I realy hope that it is fixed this time, and I also hope that alan take sover so Linus can move on to 2.5……perhaps the VM will be the first thing he makes sure works 🙂