Friday, May 23, 2008

kSar and Memory used (buffer adjusted)

Recently I found a sar graphing tool that I dreamed for more then a year: kSar

It is really a good tool that can view the sar output and export it to PNG or PDF. Really useful for me to do system status reporting for my customers.

And I can't help myself to add my dream feature to it. Here is the first one: Memory used (buffer adjusted).



In Linux system, the "memory used" value in sar (and also other tools like free) included the (1) memory used by the applications AND (2) the memory used by buffer and cache. Part 1 is usually sysadmin concern about. Part 2 is handled by the kernel automatically and it will be freed if the Part 1 increase. So in some tools like free, they will calculate a "buffer adjusted" by memused - cached - buffers. (For more information, see here or the man page of free)

This is one of the most common FAQ and I have to do the calculation on the sar data every time I want to the memory used by application. That's why I create such a patch for kSar.

Here is the patch for kSar-4.0.10: http://johnlcf.googlepages.com/kSar-4.0.10_bufferadj.patch
Here is the compiled kSar.jar with this feature as an option: http://johnlcf.googlepages.com/kSar.jar

Tuesday, May 13, 2008

HP system clock problem

Someone reported that the system clock on a HP blade system running about 2 sec/hour faster then normal. I found this report:

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c01075682