zswap – compcache, compressed swap for better performance

First, here is a link to article on compcache.

http://code.google.com/p/compcache/wiki/CompilingAndUsingNew

zswap is already in the kernel and you can see the documentation in the kernel documentation. Here is the name of the file if you need:

/usr/share/doc/kernel-doc-$(uname -r)/Documentation/vm/zswap.txt

Here is the overview, in case you do not want to install kernel-doc

Overview:

Zswap is a lightweight compressed cache for swap pages. It takes pages that are
in the process of being swapped out and attempts to compress them into a
dynamically allocated RAM-based memory pool.  zswap basically trades CPU cycles
for potentially reduced swap I/O.  This trade-off can also result in a
significant performance improvement if reads from the compressed cache are
faster than reads from a swap device.

Continue reading

pigz -parallel gzip

Here is a short description of pigz:

pigz, which stands for parallel implementation of gzip,
is a fully functional replacement for gzip that exploits
multiple processors and multiple cores to the hilt when compressing data.

And for the installation:

sudo yum install pigz

With pigz, if you don’t have many things running on your multi processor machine then you will see a significant improvement when you are gzipping the files.

concatenate compressed and uncompressed logs

<span style="font-size: x-large;"><a href="http://feedproxy.google.com/~r/Command-line-fu/~3/iwFUyltYgjM/concatenate-compressed-and-uncompressed-logs">concatenate compressed and uncompressed logs

$ find /var/log/apache2 -name 'access.loggz' -exec <a class="zem_slink freebase/guid/9202a8c04000641f800000000001abd9" title="Gzip" rel="homepage" href="http://www.gzip.org/">zcat {} ; -or -name 'access.log' -exec cat {} ; This command allows you to stream your log files, including gziped files, into one stream which can be piped to <a class="zem_slink freebase/guid/9202a8c04000641f800000000000584b" title="AWK" rel="homepage" href="http://cm.bell-labs.com/cm/cs/awkbook/index.html">awk or some other command for analysis.

Note: if your version of &#8217;find&#8217; supports it, use: