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On Tue, Aug 14, 2012 at 12:50 PM, Michael Hampicke <gentoo-user@××××.biz> wrote: |
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> Am 14.08.2012 19:42, schrieb Volker Armin Hemmann: |
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>> Am Dienstag, 14. August 2012, 13:21:35 schrieb Jason Weisberger: |
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>>> Sure, but wouldn't compression make write operations slower? And isn't he |
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>>> looking for performance? |
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>> |
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>> not really. As long as the CPU can compress faster than the disk can write |
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>> stuff. |
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>> |
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>> More interessting: is btrfs trying to be smart - only compressing compressible |
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>> stuff? |
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>> |
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> |
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> It does do that, but letting btrfs check if the files are already |
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> compressed, if you know, that they are compressed, is a waste of cpu |
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> cycles :) |
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> |
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Also look into the difference between compress and compress-force[0]. |
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I wonder how much overhead checking whether or not to compress a file |
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costs. I use mount options similar to Helmut and get great results: |
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defaults,autodefrag,space_cache,compress=lzo,subvol=@,relatime |
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But most of my data is compressible. Compression makes such a huge |
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difference, it surprises me. Apparently on this Ubuntu system it |
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automatically makes use of all files on / as a subvolume in "@". |
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Interesting. |
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Anyway, btrfs-progs does include basic fsck now but I wouldn't use it |
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for anything serious[1]. |
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[0] https://btrfs.wiki.kernel.org/index.php/Mount_options |
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[1] https://btrfs.wiki.kernel.org/index.php/Btrfsck |
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