Archive for August, 2006

RHEL4 / CentOS 4 and kernel 2.6.9-34

Saturday, August 19th, 2006

Please be aware that certain servers running stock standard kernel 2.6.9-34, 2.6.9-34.0.1 or 2.6.9-34.0.2 may experience problems with high IO wait times. You will also notice that not all the memory on the server is used.

A patch was included in the above kernels that caused the kernel to start swapping to disk long before all the memory was used. This caused serious performance issues on some servers, running the above kernel versions.

The patch was removed from the 2.6.9-42 kernel and bliss has returned to all the servers.

kernel 2.6.9-42 is also included in the RHEL 4 Update 4 and will hopefully be included in CentOS 4.4.

Plesk 8.0.1 and pleskbackup

Saturday, August 19th, 2006

Since Plesk 8 for Unix, SW-Soft, changed the backup utility from the old psadump/psarestore utilities available in Plesk 7.5.4 and earlier to the new pleskbackup/pleskrestore utilities.

I have read a lot of posts from unhappy people about the new utilities. I can honestly say that my only complaint is that SW-Soft decided to break compatibility between the pre-Plesk 8.0 and the post-Plesk 8.0 backup utilities.

That being said, the first version of the backup utilities that I tried was for Plesk 8.0.1, with at least one, maybe 2 hotfixes applied.

I have found the new Plesk 8.0.1 backup utilities to be a lot faster and a lot easier to use than their predecessors.

Yes, the backup file is still a gzipped, MIME encoded file but at least the backup utilities now add the filenames to each MIME part, making it possible to extract the backup archive into multiple clearly named files. Then it is a simple untar of the correct part to get your data.

All in all, not too bad.

By default, the new backup utilities will split your backup file into 1GB chunks. You may change this behaviour, by setting the following variable before running the backup:

PLESKX_SPLIT_SIZE=2147483648
/usr/local/psa/bin/pleskbackup –all /path/to/file/FILENAMEHERE -verbose

The PLESKX_SPLIT_SIZE variable expects a number of bytes as input. In the above example we set the chunk size to 2GB.

To be able to work with the MIME files, you will need a MIME decoder. You may want to search for mpack or get ripmime.