Dan Hollis wrote:
On Fri, 7 Jan 2005, Philip Molter wrote:
Note that if you upgrade, they also made a major change to way the
kernel handles large memory sizes (the so-called 4g/4g patch was
dropped). It probably doesn't affect a university shell server, but it
sure screwed me over.
Specifics?
Specifically, I have a machine with 4GB of memory that requires a lot of
memory listed as Buffers: (upwards of 2.5GB). This machine is very
heavy on I/O and highly tuned for its design. Not having the 4G/4G
patch, Buffers: is limited to about 600MB, and the system goes to I/O hell.
I did recompile the kernel with a 2G/2G split rather than a 1G/3G and
that helps (3G/1G is out of the question for me), but the previous 4G/4G
setup was much better for my load, even if it did use about 5-10% more
CPU (the box was, again, tuned for that extra CPU usage).
It still kind of irks me that such a major kernel change was made in a
x.y.z_a.b security release, but one can't complain too much about
software they don't pay for. Most people aren't affected by the change,
I suppose. It would've been nice if the patch was left in, so people
could recompile and enable it.
Philip