DELL PE 2850 - problems with SMP and PAE kernels
stephane at enertiasoft.com
Mon Jun 27 19:22:38 GMT 2005
I have been working with a Dell PE 2850 here recently and I've been
having some weird problems. I noticed a few previous posts about a
PE 2850 and some problems, but I think my problems are slightly
different, however somewhat similar.
I'm setting up my PE 2850 (dual 2.8 xeon, w/ 4G of RAM and a PERC4/dc
raid card) to be a mysql server. Right now, imysql is setup as a
slave to replicate from the master, with the eventual goal of
replacing the master with this server. I have ran into a couple
problems however, while running the SMP or the PAE kernel. GENERIC
seems to be okay for me.
I have the port mysql41-server installed WITH_LINUXTHREADS=yes
BUILD_OPTIMIZED=yes BUILD_STATIC=yes as I do on my other non Dell
boxes running FreeBSD 4.x and mysql.
I first attempted to run the PAE kernel to take advantage of all
4Gig's of RAM. I was pleased with performance, however while my sql
server was slaving from my master in the middle of the night it
panic'd. I wasn't at the console to see what the panic was about...
so I re-setup my server and started slaving again, this time logging
my console. This is what came up when it panic'd again:
panic: lockmgr: thread 0xfffffffe, not exclusive lock holder
I decided to try the SMP kernel out at this point as I figured I'm
hitting some bug in PAE. I booted into my kernel.old which was an
SMP build I had done earlier and everything seemed to work fine,
however I noticed my performance was terrible. Trying to re-sync
from the slave seemed to be REALLY slow. My CPU's seemed mostly idle
(95 - 99% idle) during the sync, however my system load was 1.0 - 1.5
instead of 0.33 under PAE. I couldn't explain what I was seeing...
so I decided to try GENERIC.
My experience with GENERIC was that my performance returned back to
how it was with PAE, however the system did not crash while syncing
from the sql master server. The server continues to operate and
remain synced with the master... so all seems well, for the time being.
I was hoping that someone could provide some insight in what I'm
seeing. I can run some benchmarks and tests for the time being with
this machine, as I don't plan on putting this box into production as
is until at least next week.
I also have the following in my /boot/loader.conf to allow mysql to
use up to 2Gig's of RAM on this system:
Looking at some previous posts, I noticed that people were reporting
some usb interrupt related messages, which I am also seeing, however
I don't believe this is the cause of my problems since I was running
the PAE kernel which has nodevice for the usb devices, however I
still had usbd_enable=YES in my rc.conf. Would this enable the USB
devices despite having a nodevice uhci in the kernel file?
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