Wed 10 Mar 2010
Tags: centos, dell, ipmi, linux, rhel.
Spent a few days deep in the bowels of a couple of datacentres last week,
and realised I didn't know enough about Dell's DRAC base management
controllers to use them properly. In particular, I didn't know how to
mess with the drac settings from within the OS. So spent some of today
researching that.
Turns out there are a couple of routes to do this. You can use the Dell
native tools (e.g. racadm) included in Dell's
OMSA product, or you can use
vendor-neutral IPMI,
which is well-supported by Dell DRACs. I went with the latter as it's
more cross-platform, and the tools come native with CentOS, instead of
having to setup Dell's OMSA repositories. The Dell-native tools may give
you more functionality, but for what I wanted to do IPMI seems to work
just fine.
So installation is just:
yum install OpenIPMI OpenIPMI-tools
chkconfig ipmi on
service ipmi start
and then from the local machine you can use ipmitool to access and
manipulate all kinds of useful stuff:
# IPMI commands
ipmitool help
man ipmitool
# To check firmware version
ipmitool mc info
# To reset the management controller
ipmitool mc reset [ warm | cold ]
# Show field-replaceable-unit details
ipmitool fru print
# Show sensor output
ipmitool sdr list
ipmitool sdr type list
ipmitool sdr type Temperature
ipmitool sdr type Fan
ipmitool sdr type 'Power Supply'
# Chassis commands
ipmitool chassis status
ipmitool chassis identify [<interval>] # turn on front panel identify light (default 15s)
ipmitool [chassis] power soft # initiate a soft-shutdown via acpi
ipmitool [chassis] power cycle # issue a hard power off, wait 1s, power on
ipmitool [chassis] power off # issue a hard power off
ipmitool [chassis] power on # issue a hard power on
ipmitool [chassis] power reset # issue a hard reset
# Modify boot device for next reboot
ipmitool chassis bootdev pxe
ipmitool chassis bootdev cdrom
ipmitool chassis bootdev bios
# Logging
ipmitool sel info
ipmitool sel list
ipmitool sel elist # extended list (see manpage)
ipmitool sel clear
For remote access, you need to setup user and network settings, either at boot time
on the DRAC card itself, or from the OS via ipmitool:
# Display/reset password for default root user (userid '2')
ipmitool user list 1
ipmitool user set password 2 <new_password>
# Display/configure lan settings
ipmitool lan print 1
ipmitool lan set 1 ipsrc [ static | dhcp ]
ipmitool lan set 1 ipaddr 192.168.1.101
ipmitool lan set 1 netmask 255.255.255.0
ipmitool lan set 1 defgw ipaddr 192.168.1.254
Once this is configured you should be able to connect using the 'lan' interface
to ipmitool, like this:
ipmitool -I lan -U root -H 192.168.1.101 chassis status
which will prompt you for your ipmi root password, or you can do the following:
echo <new_password> > ~/.racpasswd
chmod 600 ~/.racpasswd
and then use that password file instead of manually entering it each time:
ipmitool -I lan -U root -f ~/.racpasswd -H 192.168.1.101 chassis status
I'm using an 'ipmi' alias that looks like this:
alias ipmi='ipmitool -I lan -U root -f ~/.racpasswd -H'
# which then allows you to do the much shorter:
ipmi 192.168.1.101 chassis status
# OR
ipmi <hostname> chassis status
Finally, if you configure serial console redirection in the bios as follows:
Serial Communication -> Serial Communication: On with Console Redirection via COM2
Serial Communication -> External Serial Connector: COM2
Serial Communication -> Redirection After Boot: Disabled
then you can setup standard serial access in grub.conf and inittab on com2/ttyS1
and get serial console access via IPMI serial-over-lan using the 'lanplus' interface:
ipmitool -I lanplus -U root -f ~/.racpasswd -H 192.168.1.101 sol activate
which I typically use via a shell function:
# ipmi serial-over-lan function
isol() {
if [ -n "$1" ]; then
ipmitool -I lanplus -U root -f ~/.racpasswd -H $1 sol activate
else
echo "usage: sol <sol_ip>"
fi
}
# used like:
isol 192.168.1.101
isol <hostname>
Further reading:
Wed 24 Feb 2010
Tags: centos, linux, rpm.
Mock is a Fedora project that allows
you to build RPM packages within a chroot environment, allowing you to build
packages for other systems than the one you're running on (e.g. building CentOS 4
32-bit RPMs on a CentOS 5 64-bit host), and ensuring that all the required build
dependencies are specified correctly in the RPM spec file.
It's also pretty under-documented, so these are my notes on things I've figured out
over the last week setting up a decent mock environment on CentOS 5.
First, I'm using mock 1.0.2 from the EPEL repository, rather than older 0.6.13
available from CentOS Extras. There are apparently backward-compatibility problems
with versions of mock > 0.6, but as I'm mostly building C5 packages I decided to go
with the newer version. So installation is just:
# Install mock and python-ctypes packages (the latter for better setarch support)
$ sudo yum --enablerepo=epel install mock python-ctypes
# Add yourself to the 'mock' group that will have now been created
$ sudo usermod -G mock gavin
The mock package creates an /etc/mock directory with configs for various OS
versions (mostly Fedoras). The first thing you want to tweak there is the
site-defaults.cfg file which sets up various defaults for all your builds. Mine now
looks like this:
# /etc/mock/site-defaults.cfg
# Set this to true if you've installed python-ctypes
config_opts['internal_setarch'] = True
# Turn off ccache since it was causing errors I haven't bothered debugging
config_opts['plugin_conf']['ccache_enable'] = False
# (Optional) Fake the build hostname to report
config_opts['use_host_resolv'] = False
config_opts['files']['etc/hosts'] = """
127.0.0.1 buildbox.openfusion.com.au nox.openfusion.com.au localhost
"""
config_opts['files']['etc/resolv.conf'] = """
nameserver 127.0.0.1
"""
# Setup various rpm macros to use
config_opts['macros']['%packager'] = 'Gavin Carr <gavin@openfusion.com.au>'
config_opts['macros']['%debug_package'] = '%{nil}'
You can use the epel-5-{i386,x86_64}.cfg configs as-is if you like; I copied them
to centos-5-{i386,x86_64}.cfg versions and removed the epel 'extras', 'testing',
and 'local' repositories from the yum.conf section, since I typically want to build
using only 'core' and 'update' packages.
You can then run a test by doing:
# e.g. initialise a centos-5-i386 chroot environment
$ CONFIG=centos-5-i386
$ mock -r $CONFIG --init
which will setup an initial chroot environment using the given config. If that
seemed to work (you weren't inundated with error messages), you can try a build:
# Rebuild the given source RPM within the chroot environment
# usage: mock -r <mock_config> --rebuild /path/to/SRPM e.g.
$ mock -r $CONFIG --rebuild ~/rpmbuild/SRPMS/clix-0.3.4-1.of.src.rpm
If the build succeeds, it drops your packages into the /var/lib/mock/$CONFIG/result
directory:
$ ls -1 /var/lib/mock/$CONFIG/result
build.log
clix-0.3.4-1.of.noarch.rpm
clix-0.3.4-1.of.src.rpm
root.log
state.log
If it fails, you can check mock output, the *.log files above for more info, and/or
rerun mock with the -v flag for more verbose messaging.
A couple of final notes:
the chroot environments are cached, but rebuilding them and checking for updates
can be pretty network intensive, so you might want to consider setting up a local
repository to pull from. mrepo (available
from rpmforge) is pretty good for that.
there don't seem to be any hooks in mock to allow you to sign packages you've
built, so if you do want signed packages you need to sign them afterwards via a
rpm --resign $RPMS.
Fri 01 Jan 2010
Tags: anycast, dns, linux, sysadmin.
(Okay, brand new year - must be time to get back on the blogging wagon ...)
Linux Journal recently had a really good article
by Philip Martin on Anycast DNS. It's
well worth a read - I just want to point it out and record a cutdown version of
how I've been setting it up recently.
As the super-quick intro, anycast is the idea of providing a network service
at multiple points in a network, and then routing requests to the 'nearest'
service provider for any particular client. There's a one-to-many relationship
between an ip address and the hosts that are providing services on that address.
In the LJ article above, this means you provide a service on a /32 host address,
and then use a(n) (interior) dynamic routing protocol to advertise that address
to your internal routers. If you're a non-cisco linux shop, that means using
quagga/ospf.
The classic anycast service is dns, since it's stateless and benefits from the
high availability and low latency benefits of a distributed anycast service.
So here's my quick-and-dirty notes on setting up an anycast dns server on
CentOS/RHEL using dnsmasq for dns, and quagga zebra/ospfd for the routing.
First, setup your anycast ip address (e.g. 192.168.255.1/32) on a random
virtual loopback interface e.g. lo:0. On CentOS/RHEL, this means you want
to setup a /etc/sysconfig/network-scripts/ifcfg-lo:0 file containing:
DEVICE=lo:0
IPADDR=192.168.255.1
NETMASK=255.255.255.255
ONBOOT=yes
Setup your dns server to listen to (at least) your anycast dns interface.
With dnsmasq, I use an /etc/dnsmasq.conf config like:
interface=lo:0
domain=example.com
local=/example.com/
resolv.conf=/etc/resolv.conf.upstream
expand-hosts
domain-needed
bogus-priv
Use quagga's zebra/ospfd to advertise this host address to your internal
routers. I use a completely vanilla zebra.conf, and an /etc/quagga/ospfd.conf
config like:
hostname myhost
password mypassword
log syslog
!
router ospf
! Local segments (adjust for your network config and ospf areas)
network 192.168.1.0/24 area 0
! Anycast address redistribution
redistribute connected metric-type 1
distribute-list ANYCAST out connected
!
access-list ANYCAST permit 192.168.255.1/32
That's it. Now (as root) start everything up:
ifup lo:0
for s in dnsmasq zebra ospfd; do
service $s start
chkconfig $s on
done
tail -50f /var/log/messages
And then check on your router that the anycast dns address is getting advertised
and picked up by your router. If you're using cisco, you're probably know how to
do that; if you're using linux and quagga, the useful vtysh commands are:
show ip ospf interface <interface>
show ip ospf neighbor
show ip ospf database
show ip ospf route
show ip route
Thu 17 Sep 2009
Tags: centos, linux, skype, voip.
The new skype 2.1 beta
(woohoo - Linux users are now only 2.0 versions behind Windows, way to go Skype!)
doesn't come with a CentOS rpm, unlike earlier versions. And the Fedora packages
that are available are for FC9 and FC10, which are too recent to work on a stock
RHEL/CentOS 5 system.
So here's how I got skype working nicely on CentOS 5.3, using the static binary
tarball.
Note that while it appears skype has finally been ported to 64-bit architectures, the
only current 64-bit builds are for Ubuntu 8.10+, so installing on a 64-bit CentOS
box requires 32-bit libraries to be installed (sigh). Otherwise you get the error:
skype: /lib/ld-linux.so.2: bad ELF interpreter: No such file or directory.
# the available generic skype binaries are 32-bit, so if you're running a 64-bit
# system you need to make sure you have various 32-bit libraries installed
yum install glib2.i386 qt4.i386 zlib.i386 alsa-lib.i386 libX11.i386 \
libXv.i386 libXScrnSaver.i386
# installing to /opt (tweak to taste)
cd /tmp
wget http://www.skype.com/go/getskype-linux-beta-static
cd /opt
tar jxvf /tmp/skype_static-2.1.0.47.tar.bz2
ln -s skype_static-2.1.0.47 skype
# Setup some symlinks (the first is required for sounds to work, the second is optional)
ln -s /opt/skype /usr/share/skype
ln -s /opt/skype/skype /usr/bin/skype
You don't seem to need pulseaudio installed (at least with the static binary - I assume it's
linked in statically already).
Tangentially, if you have any video problems with your webcam, you might want to check out
the updated video drivers available in the
kmod-video4linux package from the shiny new
ELRepo.org. I'm using their updated uvcvideo module with a Logitech
QuickCam Pro 9000 and Genius Slim 1322AF, and both are working well.
Tue 15 Sep 2009
Tags: centos, linux, rhel, yum.
Found a nice post today on
how to use yum to download source RPMs,
rather than having to do a manual search on the relevant mirror.
Thu 06 Aug 2009
Tags: linux, lvm.
Lots of people make use of linux's lvm (Logical Volume Manager) for
providing services such as disk volume resizing and snapshotting under linux.
But few people seem to know about the little pvmove utility, which offers a
very powerful facility for migrating data between disk volumes on the fly.
Let's say, for example, that you have a disk volume you need to rebuild for
some reason. Perhaps you want to change the raid type you're using on it;
perhaps you want to rebuild it using larger disks. Whatever the reason, you
need to migrate all your data to another temporary disk volume so you can
rebuild your initial one.
The standard way of doing this is probably to just create a new filesystem on
your new disk volume, and then copy or rsync all the data across. But how
do you verify that you have all the data at the end of the copy, and that
nothing has changed on your original disk after the copy started? If you did
a second rsync and nothing new was copied across, and the disk usage totals
exactly match, and you remember to unmount the original disk immediately,
you might have an exact copy. But if your original disk data is changing at
all, getting a good copy of a large disk volume can actually be pretty tricky.
The elegant lvm/pvmove solution to this problem is this: instead of doing
a userspace migration between disk volumes, you add your new volume into the
existing volume group, and then tell lvm to move all the physical extents
off of your old physical volume, and the migration is magically handled by
lvm, without even needing to unmount the logical volume!
# Volume group 'extra' exists on physical volume /dev/sdc1
$ lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
data extra -wi-ao 100.00G
# Add new physical volume /dev/sdd1 into volume group
$ vgextend extra /dev/sdd1
Volume group "extra" successfully extended
$ lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
data extra -wi-ao 200.00G
# Use pvmove to move physical extents off of old /dev/sdc1 (verbose mode)
$ pvmove -v /dev/sdc1
# Lots of output in verbose mode ...
# Done - remove old physical volume
$ pvremove /dev/sdc1
$ lvs
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
data extra -wi-ao 100.00G
The joys of linux.
Tue 31 Mar 2009
Tags: linux, tips.
Note to self: here's how to get a quick overview of the hardware on a
linux box:
perl -F"\s*:\s*" -ane "chomp \$F[1];
print qq/\$F[1] / if \$F[0] =~ m/^(model name|cpu MHz)/;
print qq/\n/ if \$F[0] eq qq/\n/" /proc/cpuinfo
grep MemTotal /proc/meminfo
grep SwapTotal /proc/meminfo
fdisk -l /dev/[sh]d? 2>/dev/null | grep Disk
Particularly useful if you're auditing a bunch of machines (via an ssh
loop or clusterssh or something) and want a quick 5000-foot view of
what's there.
Fri 24 Oct 2008
Tags: centos, kvm, linux, virtualisation.
Following on from my post yesterday on "Basic KVM on CentOS 5", here's
how to setup simple bridging to allow incoming network connections to
your VM (and to get other standard network functionality like pings
working). This is a simplified/tweaked version of
Hadyn Solomon's bridging instructions.
Note this this is all done on your HOST machine, not your guest.
For CentOS:
# Install bridge-utils
yum install bridge-utils
# Add a bridge interface config file
vi /etc/sysconfig/network-scripts/ifcfg-br0
# DHCP version
ONBOOT=yes
TYPE=Bridge
DEVICE=br0
BOOTPROTO=dhcp
# OR, static version
ONBOOT=yes
TYPE=Bridge
DEVICE=br0
BOOTPROTO=static
IPADDR=xx.xx.xx.xx
NETMASK=255.255.255.0
# Make your primary interface part of this bridge e.g.
vi /etc/sysconfig/network-scripts/ifcfg-eth0
# Add:
BRIDGE=br0
# Optional: comment out BOOTPROTO/IPADDR lines, since they're
# no longer being used (the br0 takes precedence)
# Add a script to connect your guest instance to the bridge on guest boot
vi /etc/qemu-ifup
#!/bin/bash
BRIDGE=$(/sbin/ip route list | awk '/^default / { print $NF }')
/sbin/ifconfig $1 0.0.0.0 up
/usr/sbin/brctl addif $BRIDGE $1
# END OF SCRIPT
# Silence a qemu warning by creating a noop qemu-ifdown script
vi /etc/qemu-ifdown
#!/bin/bash
# END OF SCRIPT
chmod +x /etc/qemu-if*
# Test - bridged networking uses a 'tap' networking device
NAME=c5-1
qemu-kvm -hda $NAME.img -name $NAME -m ${MEM:-512} -net nic -net tap &
Done. This should give you VMs that are full network members, able to be
pinged and accessed just like a regular host. Bear in mind that this means
you'll want to setup firewalls etc. if you're not in a controlled
environment.
Notes:
- If you want to run more than one VM on your LAN, you need to set the
guest MAC address explicitly, since otherwise qemu uses a static default
that will conflict with any other similar VM on the LAN. e.g. do something
like:
# HOST_ID, identifying your host machine (2-digit hex)
HOST_ID=91
# INSTANCE, identifying the guest on this host (2-digit hex)
INSTANCE=01
# Startup, but with explicit macaddr
NAME=c5-1
qemu-kvm -hda $NAME.img -name $NAME -m ${MEM:-512} \
-net nic,macaddr=00:16:3e:${HOST_ID}:${INSTANCE}:00 -net tap &
- This doesn't use the paravirtual ('virtio') drivers that Hadyn mentions,
as these aren't available until kernel 2.6.25, so they're not available
to CentOS linux guests without a kernel upgrade.
Thu 23 Oct 2008
Tags: centos, kvm, linux, virtualisation.
I've been using kvm for my virtualisation needs lately, instead of
xen, and finding it great. Disadvantages are that it requires hardware
virtualisation support, and so only works on newer Intel/AMD CPUs.
Advantages are that it's baked into recent linux kernels, and so more
or less Just Works out of the box, no magic kernels required.
There are some pretty useful resources covering this stuff out on the
web - the following sites are particularly useful:
There's not too much specific to CentOS though, so here's the recipe
I've been using for CentOS 5:
# Confirm your CPU has virtualisation support
egrep 'vmx|svm' /proc/cpuinfo
# Install the kvm and qemu packages you need
# From the CentOS Extras repository (older):
yum install --enablerepo=extras kvm kmod-kvm qemu
# OR from my repository (for most recent kernels only):
ARCH=$(uname -i)
OF_MREPO=http://www.openfusion.com.au/mrepo/centos5-$ARCH/RPMS.of/
rpm -Uvh $OF_MREPO/openfusion-release-0.3-1.of.noarch.rpm
yum install kvm kmod-kvm qemu
# Install the appropriate kernel module - either:
modprobe kvm-intel
# OR:
modprobe kvm-amd
lsmod | grep kvm
# Check the kvm device exists
ls -l /dev/kvm
# I like to run my virtual machines as a 'kvm' user, not as root
chgrp kvm /dev/kvm
chmod 660 /dev/kvm
ls -l /dev/kvm
useradd -r -g kvm kvm
# Create a disk image to use
cd /data/images
IMAGE=centos5x.img
# Note that the specified size is a maximum - the image only uses what it needs
qemu-img create -f qcow2 $IMAGE 10G
chown kvm $IMAGE
# Boot an install ISO on your image and do the install
MEM=1024
ISO=/path/to/CentOS-5.2-x86_64-bin-DVD.iso
# ISO=/path/to/WinXP.iso
qemu-kvm -hda $IMAGE -m ${MEM:-512} -cdrom $ISO -boot d
# I usually just do a minimal install with std defaults and dhcp, and configure later
# After your install has completed restart without the -boot parameter
# This should have outgoing networking working, but pings don't work (!)
qemu-kvm -hda $IMAGE -m ${MEM:-512} &
That should be sufficient to get you up and running with basic outgoing
networking (for instance as a test desktop instance). In qemu terms this
is using 'user mode' networking which is easy but slow, so if you want
better performance, or if you want to allow incoming connections (e.g. as
a server) you need some extra magic, which I'll cover in a
"subsequent post":kvm_bridging.
Fri 23 May 2008
Tags: centos, linux, networking.
Had to setup some simple policy-based routing on CentOS again recently, and had
forgotten the exact steps. So here's the simplest recipe for CentOS that seems
to work. This assumes you have two upstream gateways (gw1 and gw2), and that
your default route is gw1, so all you're trying to do is have packets that come
in on gw2 go back out gw2.
1) Define an extra routing table e.g.
$ cat /etc/iproute2/rt_tables
#
# reserved values
#
255 local
254 main
253 default
0 unspec
#
# local tables
#
102 gw2
#
2) Add a default route via gw2 (here 172.16.2.254) to table gw2 on the
appropriate interface (here eth1) e.g.
$ cat /etc/sysconfig/network-scripts/route-eth1
default table gw2 via 172.16.2.254
3) Add an ifup-local script to add a rule to use table gw2 for eth1 packets e.g.
$ cat /etc/sysconfig/network-scripts/ifup-local
#!/bin/bash
#
# Script to add/delete routing rules for gw2 devices
#
GW2_DEVICE=eth1
GW2_LOCAL_ADDR=172.16.2.1
if [ $(basename $0) = ifdown-local ]; then
OP=del
else
OP=add
fi
if [ "$1" = "$GW2_DEVICE" ]; then
ip rule $OP from $GW2_LOCAL_ADDR table gw2
fi
4) Use the ifup-local script also as ifdown-local, to remove that rule
$ cd /etc/sysconfig/network-scripts
$ ln -s ifup-local ifdown-local
5) Restart networking, and you're done!
# service network restart
For more, see:
Mon 03 Mar 2008
Tags: linux, tips.
Find goodness (with a recent-ish find for the '-delete'):
find -L . -type l
find -L . -type l -delete
Fri 28 Sep 2007
Tags: hardware, linux.
We've been chasing a problem recently with trying to use dual
nvidia 8000-series cards with four displays. 7000-series cards
work just fine (we're mostly using 7900GSs), but with 8000-series
cards (mostly 8600GTs) we're seeing an intermittent problem with
one of the displays (and only one) going badly 'fuzzy'. It's not
a hardware problem because it moves displays and cables and
cards.
Turns out it's an nvidia driver issue, and present on the latest
100.14.11 linux drivers. Lonni from nvidia got back to us saying:
This is a known bug ... it is specific to G8x GPUs ... The
issue is still being investigated, and there is not currently
a resolution timeframe.
So this is a heads-up for anyone trying to run dual 8000-series
cards on linux and seeing this. And props to nvidia for getting
back to us really quickly and acknowledging the problem. Hopefully
there's a fix soonish so we can put these lovely cards to use.
Fri 28 Sep 2007
Tags: hardware, linux, tips.
I was building a shiny new CentOS 5.0 server today with a very nice
3ware 9650SE raid card.
Problem #1: the RedHat anaconda installer kernel doesn't support these cards
yet, so no hard drives were detected.
If you are dealing with a clueful
Linux vendor like 3ware, though, you can just go to their comprehensive
download driver page,
grab the right driver you need for your kernel, drop the files onto a
floppy disk, and boot with a 'dd' (for 'driverdisk') kernel parameter
i.e. type 'linux dd' at your boot prompt.
Problem #2: no floppy disks! So the choices were: actually exit the office
and go and buy a floppy disk, or (since this was a kickstart anyway) figure
out how to build and use a network driver image. Hmmm ...
Turns out the dd kernel parameter supports networked images out of the box.
You just specify dd=http://..., dd=ftp://..., or dd=nfs://..., giving it
the path to your driver image. So the only missing piece was putting the
3ware drivers onto a suitable disk image. I ended up doing the following:
# Decide what name you'll give to your image e.g.
DRIVER=3ware-c5-x86_64
mkdir /tmp/$DRIVER
cd /tmp/$DRIVER
# download your driver from wherever and save as $DRIVER.zip (or whatever)
# e.g. wget -O $DRIVER.zip http://www.3ware.com/KB/article.aspx?id=15080
# though this doesn't work with 3ware, as you need to agree to their
# licence agreement
# unpack your archive (assume zip here)
mkdir files
unzip -d files $DRIVER.zip
# download a suitable base image from somewhere
wget -O $DRIVER.img \
http://ftp.usf.edu/pub/freedos/files/distributions/1.0/fdboot.img
# mount your dos image
mkdir mnt
sudo mount $DRIVER.img mnt -o loop,rw
sudo cp files/* mnt
ls mnt
sudo umount mnt
Then you can just copy your $DRIVER.img somewhere web- or ftp- or
nfs-accessible, and give it the appropriate url with your dd kernel
parameter e.g.
dd=http://web/pub/3ware/3ware-c5-x86_64.img
Alternatives: here's an
interesting post
about how to this with USB keys as well, but I didn't end up going that way.
Thu 09 Aug 2007
Tags: hardware, linux.
We've been having a bit of trouble with these motherboards under linux
recently. The two S4/S5 variants are basically identical
except that the S5 has two Gbit ethernet ports where the S4 has only one,
and the S5 has a couple of extra SATA connections - we've been using both
variants. We chose these boards primarily because we wanted AM2 boards
with multiple PCIe 16x slots to use with multiple displays.
We're running on the latest BIOS, and have tested various kernels from 2.6.9
up to about 2.6.19 so far - all evidence the same the same problems. Note
that these are much more likely to be BIOS bugs, we think, than kernel
problems.
The problems we're seeing are:
kernel panics on boot due to apic problems - we can workaround by specifying
a 'noapic' kernel parameter at boot time
problems with IRQ 7 - we get the following message in the messages log
soon after boot:
kernel: irq 7: nobody cared (try booting with the "irqpoll" option)
kernel: [<c044aacb>] __report_bad_irq+0x2b/0x69
kernel: [<c044acb8>] note_interrupt+0x1af/0x1e7
kernel: [<c05700ba>] usb_hcd_irq+0x23/0x50
kernel: [<c044a2ff>] handle_IRQ_event+0x23/0x49
kernel: [<c044a3d8>] __do_IRQ+0xb3/0xe8
kernel: [<c04063f4>] do_IRQ+0x93/0xae
kernel: [<c040492e>] common_interrupt+0x1a/0x20
kernel: [<c0402b98>] default_idle+0x0/0x59
kernel: [<c0402bc9>] default_idle+0x31/0x59
kernel: [<c0402c90>] cpu_idle+0x9f/0xb9
kernel: =======================
kernel: handlers:
kernel: [<c0570097>] (usb_hcd_irq+0x0/0x50)
kernel: Disabling IRQ #7
after which IRQ 7 is disabled and whatever device is using IRQ 7 seems to
fail intermittently or just behave strangely (and "irqpoll" would just
cause hangs early in the boot process).
This second problem has been pretty annoying, and hard to diagnose because it
would affect different devices on different machines depending on what bios
settings were on and what slots devices were in. I spent a lot of time chasing
weird nvidia video card hangs which we were blaming on the binary nvidia
kernel module, which turned out to be this interrupt problem.
Similarly, if it was the sound device that happened to get that interrupt,
you'd just get choppy or garbled sound out of your sound device, when other
machines would be working flawlessly.
So after much pain, we've even managed to come up with a workaround: it turns
out that IRQ 7 is the traditional LPT port interrupt - if you ensure the
parallel port is turned on in the bios (we were religiously turning it off as
unused!) it will grab IRQ 7 for itself and all your IRQ problems just go away.
Hope that saves someone else some pain ...
