Opensuse 13.1 installation on Thinkpad T430

1. using opensuse 13.1 image from

2. format iso to bootable, ignore the warnings.

# isohybrid openSUSE-13.1-DVD-x86_64.iso
Warning: more than 1024 cylinders (4361).
Not all BIOSes will be able to boot this device.

3. write image to the flash-disk.

# cat openSUSE-13.1-DVD-x86_64.iso > /dev/sdb

4. using the flashdisk to boot T430, cleanup current partition tab, taking up full disk.


Recovery from “rm -rf /bin”

Just hit such a case, mis drop the folder “/bin”.

Enterprise Linux Enterprise Linux Server release 5.7 (Carthage)
Linux 2.6.32-100.37.1.el5uek

os still work. just /bin/ tools no longer functioning, no new access as “/bin/bash” not available.


Now what can be used: scp, vim .. and others in /usr/bin/

Lucky, to find a similar configured box, which should be the same packages version level or lower.

Im using :coreutils-5.97-23.el5
tried to find a box using :coreutils-5.97-23.el5_4.2

[root@box09 bin]# scp -r ractest@box06:/bin/ /

the bins with a bit lower version works fine within current os, as current platform libs provide a compatible runtime.
to solve the problem completely, run #yum update/reinstall to replace all binaries.


Configure Xendump for Oracle EL Linux 5.9 xen guest

this post also works for Redhat EL5 compatible.

My Configuration:

Host: testbox       2.6.18-  EL5.7
Gust: testbox-vm1   2.6.18-348.el5              EL5.9


   1. on Host, enable dumps and restart xend service.

[root@testbox xen]# vi /etc/xen/xend-config.sxp
enable dump:
  (enable-dump yes)

restart xend service:
[root@testbox xen]# service xend restart

As the root part on my box doesnt have enough space(2G+) for crash cores. using following link

[root@testbox 21_testbox-vm1]# rm -fr /var/xen/dump/
[root@testbox 21_testbox-vm1]# ln -s /var/ovs/mount/CC94A2F6CC2A4FD2957BB3FE6B6BA694/suse /var/xen/dump


   2. change vm1 guest cfg file.
[root@testbox running_pool]# pwd

[root@testbox running_pool]# cd 21_testbox-vm1/
[root@testbox 21_testbox-vm1]# vi vm.cfg
on_crash = ‘coredump-restart’     
on_reboot = ‘restart’

shutdown vm using cmd: (If the box is not yet created, no need to shutdown, just create a new.)
xm shutdown 21_testbox-vm1
restart vm using new cfg:
xm create  21_testbox-vm1 -f ./vm.cfg

3. inside vm1.

enable sysrq:

kernel.sysrq = 1

       choosing RH compatible kernel, instead of the UEK kernel for dumps.
--OEL5 UEK kernel not working well with xendump service.

[root@testbox-vm1 ~]#  vi /etc/grub.conf
default=1    <– the # of RH kernel

We are now using kernel:
Install following RPMs for further cases:


reboot the guest, root access and issue:
[root@testbox-vm1 ~]# echo c >/proc/sysrq-trigger

a new core was generated in Host:

[root@testbox dump]# pwd
[root@testbox dump]# ls


4. how to analyze the core.

scp the core into testbox-vm1. for example:
(there should be some other ways to share files between guest/host, like via NFS)

[root@testbox-vm1 0013]# pwd
[root@testbox-vm1 0013]# ls

        issue crash utility:



[suse@suse ~]$ssh root@testbox-vm1
[root@testbox-vm1 ~]# echo c >/proc/sysrq-trigger

a new core (sizeof 2G, memsize of the guest vm1) is generated in testbox:/var/xen/dump

How to enable automatic core dumps of xen guests?
Core dump Xen domU/guests


cisco anyconnect failed due to /etc/resolv.conf settings

[Error: ]

Cisco anyconnect failed:


failed anytime at the final step.

[root cause:]

the root cause is the xattr setting on /etc/resolv.conf
I was using pppoe connection last days, and setting /etc/resolv.conf with a fixed value.

cisco anyconnect will try anyway to replace/update items in /etc/resolv.conf. failed if no update permission.

I used “chattr +i ” to keep the file stable, but it failed to update and cisco anyconnect will give up connection at last.


chattr -i /etc/resolv.conf