gzip compression of log files

[catlee]

It should be possible to choose between bzip2 and gzip compression for log files. gzip is much faster, at the cost of compression ratio.

We've hit a few cases with multi-gigabyte logs files taking a really long time to compress with bzip2 on the master, making it very sluggish.

Here are some timings of compressing the original 3.8 GB log file with the standalone gzip / bzip2 tools:

bzip2: 0:57:29, 4.5 MB
gzip: 0:01:58, 23 MB

I'd happily trade 20 MB of disk space for almost an hour of CPU time.

[dustin]

This got committed.

[Nicolas]

Fixed in  8d6d4b7.