Linux LVM is a wonderful thing. It is scalable, flexible, and truly, almost enterprise-class in every details. It lacks, of course, at IO performance for LVM snapshots, but this can be worked-around in several creative ways (if I haven’t shown here before, I will sometime). What it can’t do is dealing with a mixture of…
Most documentation on the net is about how to run a cluster-in-a-box under Vmware. Very few seem to care about protecting Vmware guests under real RedHat cluster with a shared storage. This article is just about it. While I would not recommend using Vmware in such a setup, it has been the case, and that…
For some reason (probably a typo) I’ve missed an important character in an example I gave here, but I have just recently fixed it. Anyhow, to clarify this, here is the extended description of the correction. The $IFS Bash system variable defines what is the default separator between strings. Changing it can help when dealing…
First and unrelated – this is my birthday. It reminds me that another year passed, and generally speaking, I do not take this too well… Due to massive SPAM attacks, my commenting system is turned off for a while now, and I need to see how I can re-enable it safely. Bash – here we…
This was a tricky action. Assume I have a list of variables, obtained by an external source: var1=a var2=b var3=c I cannot use loop and in it the phrase ${var$i} (where i is the integer counter). It just doesn’t work. I used this instead to assign the values to an array: var[$i]=$(eval echo "${var${i}}") That…
Let’s assume we have a file containing lines such as this: first last one two three four five If we write a simple script to deal with each line in a turn, we would write something like this: for i in `cat file`; do echo $i; done This would echo, however, each word at its…
