Tag: backup

Fast appending files to tar archive is impossible.

Eventually, tar is very slow for appending files to the existing tarball. I’m particularly talking about following options:

-r – append files to the end of an archive
-u – only append files newer than copy in archive

Logically thinking, for -u to work, it should accomplish linear search through the archive. Than bigger the archive, than slower the search. Moreover, if you’ll try to append in the loop, it will accomplish search as many times as many iterations you loop has. I would advice to use in the most exceptional case ONLY. Try avoiding

# -u. slow inefficient approach of taring multiple files
for file in $(ls -A)
    tar -uf tarball.tar $file;		#traverses all archive to append the file.

You’d think that -r option usage forces tar application to append files to the end of the archive, getting the position of the archive’s end from archive’s index. It doesn’t. Tar format is designed in a way that it has no index.

# -r approach is also slow and inefficient
for file in $(ls -A)
    tar -rf tarball.tar $file;		#traverses all archive to append the file.

However, TAR supports several formats for its archive. But they are not well-documented. I had a brief overview of them, and looks like
–format=gnu is the most recent and featured one. And It still has no index. I no longer understand why tar is even used. Despite of that, below is a workaround, allowing for packing unlimited amounts of files right instant. I recommend to never use append function with tar format. Instead, get to know what are you going to archive, prepare necessary files, and archive them all.

# faster approach for taring multiple files. No appending
ls -A >> list.txt
tar -cT list.txt -f backup.tar

WordPress as a Perfect Livejournal Backup Tool.

I have a livejournal account. Being system administrator, I am concerned about backup. But oops! Built-in livejournal backup tool is a mess. The tool tries to be as much inconvenient as possible. It allows you to export posts for a period of one month at once only. For a perin of one month only. ONE MONTH ONLY.

I’ve been looking around for another utility to backup my journal. Useless. None of them worked for me in a proper convenient way. No, my demands were not impossible to satisfy. I wanted to import posts only. No comments, no visibility – only texts. I gave up and did my backup using native tool (arggh).

Greet the savior! Ave WordPress! It can import all your livejournal including hidden posts and all comments with a status of their visibility. You’d say, ok I have imported it. What is next? Well, you can stop at this point. If you used WordPress.com, you can keep private copy of your livejournal, or you can hide all posts and use wordpress.com as your online storage (security!).

I’m not done yet. You can export your wordpress contents as XML file. And if it contains you livejournal copy, you already understand me, don’t you? Yes, it’s Profit.