by Pedro M. S. Oliveira | Jul 13, 2010 | Linux
Linux is not Windows and if reboot fail you usually still connect by SSH and do something. This commands will show you how to remotely hard reboot machine.
Hard reboot mean that shutdown scripts will not run and machine reboot immediately without syncing hard disk drives, shutdown applications etc, it’s like hitting the reset button on your server.
echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger
This commands enable sysrq and after this calls fast reboot. If you want to force shutdown machine try this.
Force shutdown
echo 1 > /proc/sys/kernel/sysrq
echo o > /proc/sysrq-trigger
This came handy, when I had a server that had some IO error and it can no longer read from disk, only few cached binaries into memory kept it running (kernel, SSHD, bash), I could still access the machine via SSH but can no longer do anything, forcing the reboot as mentioned above was my only resort, and it worked like charm…
by Pedro M. S. Oliveira | Sep 27, 2009 | Linux
This weekend I’ve had some free time so I tested a new kernel on my suse 11.1 x86_64 system. I’ve been a beta tester for the kernel for some time and I was eager to test the final version.
There are plenty new features, the one I enjoy more are probably on the filesystem area but there is plenty to choose.
This version adds USB 3.0 support, a equivalent of FUSE for character devices used for proxying OSS sound to ALSA, some memory management changes that improve interactivity in desktops, readahead improvements, ATI Radeon Modesetting support, support for Intel’s Wireless Multicomm 3200 Wifi devices, kernel support and a userspace tool for performance counters, gcov support, a memory checker for unitialized memory, a memory leak detector, a reimplementation of inotify and dnotify on top of a new filesystem notification infrastructure, btrfs improvements, support for the IEEE 802.15.4 network standard, IPv4 over Firewire, many new drivers, small improvements and fixes.
You may see the hole list here:
http://kernelnewbies.org/Linux_2_6_31
I still didn’t do extensive testing but so far so good ;), although my kde4.3 seams to lag a bit, I’m not sure if this is from the new kernel or the changes I’ve done within KDE itself.
On the other end with server machines it works perfectly, i’m doing stress tests on two virtual servers and memory usage / IO times / CPU usage.
On the test i’m using two opensuse 11.1 x86_64, one as 2.6.27 kernel version and the other 2.6.31, same amount of memory and 2 cpu each on the same host. Hope to have some more data in a few days and then post the results (cacti graphs) here if they are relevant.
So, what are you waiting for… TRY IT
Cheers
Pedro Oliveira
