What’s the ‘best’ file compression method?

I’ve been doing a little bit of research into the best compression method to use in Ubuntu. There’s so many compression types when I right click –> create archive. Keep in mind that I’m simply using the default compression values right from the desktop, there’s no special tweaking involved here. Mainly, I want something quick and easy for every day file management. Many of these formats, I’ve seen before and had heard some were ‘better than others’; some faster, and some compress more. I really wasn’t sure what’s the best option.

I often have large data files (hudreds of megs or larger) that I like to make backup copy of, but would rather store them in a compressed format. I also don’t want to wait around forever to get the job done. I’m working on a fast machine (duo core 2) with a gig of memory.

So what’s gave me the ‘best’ results when compressing my 1.4 gb file? It’s a virtualbox .vdi file, essentially the entire HD for a windows 2000 virtual machine. The results could be very different on a collection of lots of small little files… something I might test later. In the mean time there’s a good study already published here.

Here’s my test results of several different formats on the file:

Best compression – size in MB.

1. 7z 493
2. rar 523
3. bz2 592
4. lzh 607
5. gz 614
6. Z 614
7. zip 614
8. .arj 615
9. lzo 737
10. zoo 890

Best Time in seconds

1. zip 175
2. zoo 186
3. arj 253
4. lzo 295
5. Z 300
6. gz 344
7. lzh 657
8. bz2 706
9. rar 840
10. 7z 896

Conclusions:

It came as a surprise to me that plain old .zip to which I am quite familiar with already, is still a better choice for high compression of large data files in a short amount of time.

.arj and .Z and .gz all compress about as much, but just not as fast as .zip

I’ve heard really good things about .7z and it’s ability for high compression, and it does show in the results.  Both .z7 and .rar are able to use the duo core processor better (cpu use at 77%-90% compared to 55% for the others) yet take much longer than anything else to compress. If the file were being uploaded onto the internet, perhaps I would choose for the highest compression even it it takes 4 times longer.

I had read that .lzo and .zoo were good (some people claimed they were better) and fast with high compression, but I just don’t see that here at all.  They’re way off the mark.

So whats the best option?

.zip for quick and compatible compression.

.rar for high compression and compatiblity, when you have the time to wait.

.z7 for maximum compression when you have the time to wait.