Lzma Vs Bzip2 (Stability and performance)
Dear all,
I have been reading the following link, that is about lzma performance compred to bzip2. Lzma Vs Bzip2 – Better Compression than bzip2 on UNIX / Linux I would like to ask you if you have the same feeling that the article claims that lzma can achieve a better of compressed ratio. Moreover, I would like to ask you if the lzma is well supported in linux (in terms that I can download it and start using it, without major and minor bugs floating around).I I would like to thank you in advance for your reply Regards Alex |
I don't see the link into your post :)
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I recommend LZMA2 = xz. Yes it has been well tested and should be mostly bug-free. If you want the best compression algorithm available, then this is it.
On a daily basis, however, I still use gz, because it is much faster and I've got plenty of space on the disk. |
Hi,
thanks for the answer. In my opensuse I have actually almost all the tools man lzma returns at header Quote:
2. I just wonder if tar and the aforementioned algorithms were made with large files in mind. For example, I have a tar of 1.2 TB that should be largely compressible, file includes mostly sequences of 0s and 1s.... I have found though in the man lzma the following text Quote:
Alex |
If you have enough RAM and a fast processor, lzma2 is great. You can also play with dictionary size to get even better ratios especially since you say your files have a lot of repetitive sequences.
The easiest way to find out is to try both. In my experience with everyday files you want to compress (backups,) the difference between bzip2 and lzma2 is minimal and rarely justifies the extra time and memory lzma2 requires. |
It would depend on data to be compressed as inferred by designator. My guess is that most people could depend on LZMA to provide better results in general data if newish system.
It is quite easy to use older tools and provide backward support for older systems. That may be a reason to use older means. Also consider the ability of your apps to use smp. The newer tools tend to use multiple cpu's much better. |
Wow, 1.2 TB ... that will probably take a long time to compress (days). Maybe try gzip first, because it is much faster.
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Hi I have did with gzip -9 as it finishes in only 4 days...
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Ouch! "gzip -9 as it finishes in only 4 days..."
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Indeed I had the xz also running at the first four days. It had only written 44GigaBytes and as the source was 1.2T I though this will takes months to finish :p
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LZMA is definitely better than bzip2. But it's also a lot slower.
Actually, there are barely any tasks that require compression these days. Algorithms like gzip/bzip2/lzma are designed to compress text, not binary data. So it's good for, say, a lot of source code (Linux kernel). But when you try to compress images, videos, other binary stuff, you just waste your time because processing several GB of that data will take you a lot of time and you will only save maybe a couple of megabytes of space... And then you'll transfer it through Internet with speed like 3 MB/s. Thus it will save you about 1 second of transferring and take several hours to compress and then decompress. |
This benchmark is relevant:
http://stephane.lesimple.fr/blog/201...-reloaded.html |
Those kind of numbers should make you look at using way lower compression settings. Seems your system is pretty much low on resources during all of this. All the compression tools rely on processor(s). Newer tools might rely on smp above 4 cores.
I use some very very (very) old computers to back up a qnx system. Even at 1.5G it gets done in 2 or 3 hours. |
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