[plug] 2.4.24 mremap root exploit

[Craig Ringer]

On Wed, 2004-02-18 at 22:33, William Kenworthy wrote:
> Interesting to see how it goes.  Subjectively nicer on the desktop, but
> ~1/3 slower using transcode which fits in with others have said on the
> gentoo lists (The first guy who brought it up (posted the numbers) 
> started a mini-flamewar for suggesting 2.6 could be slower!)

Heh... of course it's slower for some tasks - isn't every major OS
upgrade, esp when developed for scalability? Who cares though - really?
If it's more solid and consistent in performance, and more responsive,
I'd consider that a worthwhile trade-off. I must admit surprise at how
/much/ slower he reported - I'd expect no more than a max slowdown of 5
- 10% in a worst case to have been allowed. Driver issue perhaps?

Personally, I'm hoping that system snapshots and other large periodic
backups will no longer cause random stalls and apalling read latencies.
Especially if the CPU and disk write storm created by a flood of SPAM
has a less noticeable effect on system performance. Anything else is a
bonus. I must say, though, that so far it /feels/ faster or "snappier"
(tending to imply more responsive, rather than higher "power" or
throughput). When one has NFS (inc. LTSP root-fs), SMTP, IMAP,
MimeDefang, ClamAV, SpamAssassin, Appletalk, DHCP, SMB, 20 active users
running OO.o+mozilla+XFCE4 or OO.o+GNOME+Evolution, and maybe a system
backup running, responsive multitasking and low latency are _good_
things.

Alas, our poor NT server can't seem to understand CIFS, so we're still
stuck on smbfs with it's quirks and limited charset. Mac users seem to
_love_ using the characters /\*?'"()| (and the less annoying ~&) in
filenames, and this makes network backups /lots/ of fun.

BTW, Anybody else on PLUG running 2.6 in production? I'm really just
trialling it, but it's a live trial because of user demands and
management agreeing with the users.

If anybody wants tips on upgrading an older server running LVM1 (RH8, in
this case) to 2.6.x with LVM2, feel free to ask. It's trickier than it
could be :-( but not overly difficult.

--
Craig Ringer