Monitor dmesg in real time with watch.

watch "dmesg | tail -20"

Analyze the boot process with the blame command ARCH linux

Install graphics tools in ARCH

pacman -S eog dot2tex

Script
#-------------------------------
#!/bin/bash

systemd-analyze
systemd-analyze blame
systemd-analyze plot > /tmp/graph.svg
systemd-analyze dot | dot -Tsvg > /tmp/dot-graph.svg
echo "Show graph
eog /tmp/graph.svg 
eog /tmp/dot-graph.svg
"
#------------------------------- 

Plot svg graph example

Plot svg dot-graph example

Problem with SMART probing sata disk on some chipsets/sata controllers results system is freeze (ata exception frozen).

Very annoying linux / hardware bug triggered by SMART ata check it only manifests in some cases of SATA controllers and hard disks. In my case:

On M3A32-MVP DELUXE controller

Marvell Technology Group Ltd. 88SE6121 SATA II / PATA Controller

Error in /ver/log/messages looks like this:

[  115.670018] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen

[  115.670027] ata5.00: failed command: SMART

[  115.670036] ata5.00: cmd b0/d0:01:00:4f:c2/00:00:00:00:00/00 tag 0 pio 512 in

         res 40/00:01:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)

[  115.670039] ata5.00: status: { DRDY }

[  115.670047] ata5: hard resetting link

[  115.989123] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300)

[  116.088351] ata5.00: configured for UDMA/133

[  116.088380] ata5: EH complete

[ 7300.699855] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen

[ 7300.699863] ata5.00: failed command: IDENTIFY DEVICE

[ 7300.699872] ata5.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 0 pio 512 in

         res 40/00:00:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)

[ 7300.699876] ata5.00: status: { DRDY }

[ 7300.699883] ata5: hard resetting link

[ 7301.019187] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300)

[ 7301.131523] ata5.00: configured for UDMA/133

[ 7301.131557] ata5: EH complete

Bug reports 

https://bugs.freedesktop.org/show_bug.cgi?id=54905

https://bugs.launchpad.net/ubuntu/+source/libatasmart/+bug/445852

https://bugzilla.redhat.com/show_bug.cgi?id=549981

Solution  - testing 

Gentoo udev rules are located in /usr/lib/udev/rules.d

Locate 80-udisks.rules and remove following line:

KERNEL=="sd*[!0-9]", ATTR{removable}=="0", ENV{ID_BUS}=="ata", ENV{DEVTYPE}=="disk", IMPORT{program}="udisks-probe-ata-smart $tempnode"

Rrepeat every time after update of udev.

SElinux problems running custom build Apache

#Install SELinux trubleshoot
yum install setroubleshoot-doc.x86_64 setroubleshoot-plugins.noarch setroubleshoot.x86_64 setroubleshoot-server.x86_64

#This clears whole audit.log use with cotion
#echo ""> /var/log/audit/audit.log

#Run sealert -a to see the problem recomandation
sealert -a /var/log/audit/audit.log

#Run this to what should be done grep by blocked aplication
grep httpd /var/log/audit/audit.log | audit2allow

#Create exceptin module
grep httpd /var/log/audit/audit.log | audit2allow -M apache

#Install custom module to permit exception
semodule -i apache-unlink.pp

#Remove module if its is not neded
semodule -r apache-unlink.pp

#SELinux Labeling file and dirs
semanage fcontext -a -t httpd_sys_content_t '/var/www(/.*)?'

#Apply new policy on files
 restorecon -R -v /var/www

#Copy SELinux policy lable
chcon --reference=/usr/bin/test /usr/bin/test1

#Apply new policy on file
restorecon -v /usr/bin/test1

#Human readable events
cat /var/log/audit/audit.log | ausearch -i |less

#Human readable events realtime
tail -f /var/log/audit/audit.log | ausearch -i

OracleVM 3 PW drivers for Oracle Linux 5u7

So, to boot OL5U7, you pass xen_emul_unplug=never on the kernel boot line, which allows the machine to boot with the emulated devices, i.e. they are not unplugged.

Then, edit /etc/modprobe.conf to replace the emulated devices with xen-netfront and xen-blkfront:
Fiel /etc/modprobe.conf should look like this:
alias eth0 xen-netfront
alias scsi_hostadapter xen-blkfront

Then, rebuild initrd:
mkinitrd -f -v --builtin=ehci-hcd --builtin=ohci-hcd --builtin=uhci-hcd /boot/initrd-`uname -r`.img `uname -r`

And reboot. You may get kudzu renaming ifcfg-eth0 to ifcfg-eth0.bak on reboot, because it detects "new" hardware. If so, just rename it back and it should be fine.

Nepomuk reindexing everything after restart

Nepomuk reindexing everything after restart
In your ~/.kde[4]/share/config/nepomukstrigirc file is the the the "first run=" option false?

PV-HWM drivers OracleVM 3.0.2 - 3.0.3

In file /etc/modprobe.conf this should be present

#alias eth0 8139cp
#alias scsi_hostadapter ata_piix
alias net-pf-10 off
alias ipv6 off
options ipv6 disable=1
alias sym53c8xx off
alias scsi_hostadapter xen-vbd
alias eth0 xen_vnif

and initrd shut be regenerated

mv /boot/initrd-2.6.18-274.el5.img /boot/initrd-2.6.18-274.el5.img.old ;
mkinitrd -v /boot/initrd-2.6.18-274.el5.img 2.6.18-274.el5 --with=xen-vbd --with=xen-vnif --preload=xen-balloon --preload=xen-platform-pci

LVM filter update

After LVM filter update LVM cache has to be removed

# By default we accept every block device:
#filter = [ "a/.*/" ] default
filter = [ "a|/dev/mpath/notblacklisteddevice|", "r|.*|" ]

rm /etc/lvm/cache/.cache
vgscan