*.sql vs *.gz

[DJ RRebel]

ok ... first let me state the obvious in that although I understand some concepts of SQL, I'm far from being an expert.

My problem lies in that my vB database is way too big to back-up through vB, and everytime i want to do a back-up, I have to call my host's tech and get them to do a manual 'MySQL dump on the command line'.

Usually this is fine ... but sometimes they do it in *.gz format (even if I specifically ask for it in *.sql).

I've noticed that when I uncompress the *.gz file (which results in a *.sql file), the *.sql is about 2% to 4% smaller than than the corresponding *.sql file that was originally a *.sql file (never compressed).

Considering my *.sql files are about 300 megs for a complete back-up, having a difference of over 5 megs is both perplexing and worrysome.

It seems saving to *.gz seems to be much simpler for them to do, but I can't have the peace of mind I get from a *.sql (never compressed) back-up when it is done via *.gz ...


Could someone please give me a quick explanation of *.gz files, and any potential reasons why the *.sql file uncompressed from a *.gz file is not the same size as the *.sql file that was never compressed ???

Also ... considering what I've mentioned above, what would you recommend I do from now on ??? Get them to do it in *.sql format? Or get it done as a *.gz (which I think I can actually do myself through cPanel5's backup ['download a SQL DB Backup'])


Finally ... is the cpanel backup *.gz file a non-live back-up done automatically once every X hours or X days), or is it created when I attempt the download ... is this feature reliable?

So ... to summorise:

1- Why is a *.sql from a *.gz smaller than a *.sql that was never compressed?

2- How should I back things up in the future (*.gz or *.sql)?

3- How reliable is cPanel5's back-up feature, and is it a 'live' back-up, or simply a file that is saved every X amount of time ???


I really want to start getting more involved in tweeks and hacks ... but I really think the best first step in getting there is actually being able to successfully back-up my data ... lol ... or at the very least ... know when I have a reliable back-up (rather than just hoping my host's tech sent me a complete back-up or not).


Anyhow ... Thanks tons for your feedback and help !!!