Archive
Posts from 2005
Veritas Volume Manager Recovery Features
It looks like SysAdmin magazine just published my article titled Veritas Volume Manager Recovery Features. If you are looking for ways to increase system recoverability and to get alerted when issues popup in VxVM environments, you may enjoy this article
$ read more →Solaris 10 Apache DTrace module
I sent the following e-mail message to the DTrace mailing list today announcing the release of mod_dtrace version 0.2a: I have been working on an Apache DTrace module for the past few weeks, and just released version 0.2a. This module integrates Dtrace probes into Apache through the Apache hook framework. These probes can be used to observe and correlate a wide-variety of application and system behavior, which I have found useful for correlating network and virtual memory events with the requests served by Apache. I have written a few scripts to show some of the things I have been able to do with mod_dtrace, and have attached [1] some screenshots to this e-mail…
$ read more →Monitoring Apache memory allocation with DTrace
The Apache web server uses an abstraction concept called a pool to simplify memory management in the Apache web server. Memory can be allocated and assigned to a pool (there are several pools, with different lifetimes depending on how long the memory needs to stick around) through numerous routines, including the apr_palloc() routine. This routine contains the following prototype: apr_palloc() and the underlying allocator routines try to allocated memory in chunks, which ensures that brk() and company aren't called excessively. To get a better idea of how often apr_palloc() requested memory from chunks already allocated (the underlying allocator uses malloc() ), I created the following D script: Wow -- apr_palloc() was called 671 times for 3 GET requests, and malloc() was called 22 times to meet the demand for memory (this is another reason why it's a good idea to comment out unused modules)…
$ read more →Debugging Apache
If you ever find the need to debug Apache and want stop httpd from forking and detaching from the controlling terminal, you can start httpd with the ONE_PROCESS and NO_DETACH options: Once you are done debugging, you can hit control-c and the process will exit. Giddie up!
$ read more →Time for Sun to retire smpatch
Ugh -- I went to patch my machines today, and it looks like the smpatch(1m) utility is broken again: I appreciate what Sun is trying to do with this utility, but it is causing users and administrators a lot of pain. If anyone from Sun is reading this, can you please revert back to Recommended patch clusters until smpatch is permanently fixed?
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