Is gzip or gzip -9 for a disk clone worth the extra time that it takes to perform the compression? Does it yield a significant saving?

There is very little information on how effective piping data from dd thru gzip really is. (Some data simply doesn't compress well, is the data stream of a disk that compress-able?

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    This will likely get closed as not constructive, as it should be. If you have a hard drive full of text files, then it will be very much worth it. If you have a hard drive full of encrypted data, then no. It all depends on your situation.
    – EEAA
    Nov 16, 2011 at 3:18

2 Answers 2


You give the answer by yourself:

Some data simply doesn't compress well

... and other data extremely well. That said, it completely depends on the type of the data you have on that HDD: are they mostly text? or mostly MP3 files, videos, images? If it mixed, it might be worth splitting up in two partitions instead.


The real first question is "what data are you piping in?" Based off the tag of "backups" I'm going to assume we're talking about hard drive images.

In that case, yes, gzip is definitely worth the time. On a recent Linux partition I gzip'd, the file went from 1.7gb to ~200mb, which definitely paid for itself in time savings while uploading.

The higher compression options are very rarely worth the additional time, in my experience. If you're creating a file that will be downloaded over very slow links, then it might be worth it. In general, though, it won't cause much space gains over the default compression levels.

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