Re: Linux I/O tuning: CFQ vs. deadline

david(at)lang(dot)hm wrote:
> most of my new hardware has no problems with the old kernels as well,
> but once in a while I run into something that doesn't work.

Quick survey just of what's within 20 feet of me:
-Primary desktop: 2 years old, requires 2.6.23 or later for SATA to work
-Server: 3 years old, requires 2.6.22 or later for the Areca card not
to panic under load
-Laptops: both about 2 years old, and require 2.6.28 to work at all;
mostly wireless issues, but some power management ones that impact the
processor working right too, occasional SATA ones too.

I'm looking into a new primary desktop to step up to 8 HT cores; I fully
expect it won't boot anything older than 2.6.28 and may take an even
newer kernel just for basic processor and disks parts to work.

We're kind of at a worst-case point right now for this sort of thing, on
the tail side of the almost 3 year old RHEL5 using a 3.5 year old kernel
as the standard for so many Linux server deployments. Until RHEL6 is
ready to go, there's little motivation for the people who make server
hardware to get all their drivers perfect in the newer kernels. Just
after that ships will probably be a good time to do that sort of
comparison, like it was possible to easily compare RHEL4 using 2.6.9 and
RHEL5 with 2.6.18 easily in mid to late 2007 with many bits of
high-performance hardware known to work well on each.

--
Greg Smith 2ndQuadrant Baltimore, MD
PostgreSQL Training, Services and Support
greg(at)2ndQuadrant(dot)com www.2ndQuadrant.com