access_log gzipping временно замораживает апачский сервер

Definitely NOT normal. Three things to check:

1. Make sure the log rotation system doesn't try to compress tle log Apache is writing to. You can do this by setting the "DelayCompress" flag in logrotate's config file.
2. Make sure your logrotate configuration has a postrotate command that makes Apache re-open its logfiles (graceful restart should be OK).
3. In the (very unlikely) event that gzip is saturating your CPU, see if you can renice the gzip process (Not sure if logrotate supports that but you could hack it with a postrotate script)