Messages in this thread | | | Date | Mon, 10 Oct 2005 10:45:35 +0200 | From | Pavel Machek <> | Subject | Re: Linux Kernel Dump Summit 2005 |
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Hi!
> FULL DUMP WITH COMPRESSION > ========================== > > Those who still want a full dump, including me, are interested > in dump compression. For example, the LKCD format (at least v7 > format) supports pagewise compression with the deflate > algorithm. A dump analyze tool "crash" can transparently > analyze the compressed dump file in this format. > > The compression will reduce the storage space at certain degree, > and may also reduce the time if a dump process were I/O bounded.
I'd say that compression does not help much, it can only speed it up twice. But...
> > WHICH IS BETTER? > ================ > > I wrote a small compression tool for LKCD v7 format to see how > effective the compression is, and it turned out that the time > and size of compression were very much similar to that of gzip, > not surprisingly. > > Compressing a 32GB dump file took about 40 minutes on Pentium 4 > Xeon 3.0GHz, which is not good enough because the dump without > compression took only 5 minutes; eight times slower.
....you probably want to look at suspend2.net project. They have special compressor aimed at compressing exactly this kind of data, fast enough to be improvement. Pavel
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