Sanlock helps you avoid screwing things up by starting the same virtual machine on multiple hosts, which will quickly mangle the guest file systems. But you’ll quickly find live migration no longer works from the virt-manager GUI.
I was in shock when I first saw this migration error from virt-manager!
Internal error cannot use migrate v2 protocol with lock manager sanlock? But alas, all is not lost.
Migration from the virsh command shell works just fine for me. And it’s quicker and more efficient than doing it pointy-clicky style from a gui anyway. If i’m migrating a guest from one host to another, it’s usually because I need to shut down the host hardware. I’m not migrating just one guest, i’m migrating one at a time.
With the shell method, I repeat the migration command in a loop and move them all, one after another automatically. Monday migrate, tuesday migrate, everybody. It’ll get in your bones!
root@host1~# for x in 1 2 3 4 5 6 7 8; do
virsh migrate –live guest$x qemu+ssh://host2/system
When I first set up sanlock for qemu locking, I saw errors during migration of several hosts that were already up and running with local locking before sanlock locking was implemented.
error: … Read More »
Most guides telling you how to mount smb CIFS/Samba shares on Linux to mount on Windows 7 will point you to adjust settings in Administrative Tools -> Local Policies. Windows 7 Home Premium does not have the Local Policies MMC snap-in. Therefore you cannot use that tool to change the NTLMv2 security settings.
Making a basic C style python struct is a simple one liner. But why stop here? The least you could do is implement some built in class methods. Ok it’s a silly example, but implement some fun things and before you know it you’ll have a full blown class on your hands.
The fastestmirror plugin for yum is supposed to make updates and installations faster right? What if you have to wait for a fastestmirror timeout before yum continues installing?
More like slowestmirror
If all the mirrors are timing out and appear dead because of some network issue such as a restricted firewall or proxy, the wait is painful.
Turn on verbosity first. Edit /etc/yum/pluginconf.d/fastestmirror.conf and set verbose=1 then try updating or installing a package.
After a short delay you should start to see responses from all the mirrors.
# yum install patchutils
Loaded plugins: fastestmirror, presto
Loading mirror speeds from cached hostfile
* centos.mirror.constant.com : dead
* centos.mirror.constant.com : 99999999999.000000 secs
* centosmirror.quintex.com : dead
* centosmirror.quintex.com : 99999999999.000000 secs
* mirror.linux.duke.edu : dead
* mirror.linux.duke.edu : 99999999999.000000 secs
* mirrors.liquidweb.com : dead
* mirrors.liquidweb.com : 99999999999.000000 secs
* mirror.cs.vt.edu : dead
* mirror.cs.vt.edu : 99999999999.000000 secs
* mirror.liberty.edu : dead
* mirror.liberty.edu : 99999999999.000000 secs
* mirror.rackspace.com : dead
* mirror.rackspace.com : 99999999999.000000 secs
* bay.uchicago.edu : dead
* bay.uchicago.edu : 99999999999.000000 secs
* mirror.raystedman.net : dead
* mirror.raystedman.net : 99999999999.000000 secs
* ftp.osuosl.org : dead
* ftp.osuosl.org : 99999999999.000000 secs
If you’ve just got a few timing out, just add exclude’s to the configuration file so it skips them. Conversely, you can add a whitelist of the fastest responders to speed things up.
Fastestmirror timeout still?
If your firewall or proxy is completely blocking the fastestmirror plugin because it’s ignoring http_proxy style environtment variables and your proxy setting in yum.conf, then you’re pretty much out of luck with this plugin.
You can’t remove the package because of dependencies, so just turn it off in the config. Edit /etc/yum/pluginconf.d/fastestmirror.conf and set enabled=0
If you’re behind a proxy and don’t have yum configured yet, try adding your proxy to yum.conf first.
Backing up an OpenLDAP installation is a very easy and non-intrusive process. You can backup the database while the old slapd is running using slapcat, so there’s no need for interruption while setting up the new instance. In my example, I will not backup individual databases with -n switch. I want the whole thing in one giant ldif because i’m going to restore the whole thing at once too. Keep it simple.
Just hit CTRL-C and it will fail this method and then connect through your proxy to download the file. But do you really want to do that a hundred times? It will take quite a long time to install even if you sat there sending breaks each time. If you’re getting this far, you’ve got curl installed already, probably through the libcurl rpm that came with your Linux distribution. But there’s no /etc/conf file to set a proxy in, and it’s not honoring the environment variable.
Send the USR1 signal to the pid using the kill command. Sending -9 or -15 will most definitely kill the dd, but sending the USR1 signal will output the current progress instead.