From: Mitch Harder <email@example.com> To: Philip Worrall <firstname.lastname@example.org> Cc: linux-btrfs <email@example.com> Subject: Re: [PATCH 0/8] Add support for LZ4 compression Date: Mon, 2 Jun 2014 17:04:02 -0500 Message-ID: <CAKcLGm9nHmmN1oAe2AQO6aNB8R6nmqvwjUv+9ytiUFD5LWG3nw@mail.gmail.com> (raw) In-Reply-To: <firstname.lastname@example.org> On Sat, May 31, 2014 at 6:48 PM, Philip Worrall <email@example.com> wrote: > LZ4 is a lossless data compression algorithm that is focused on > compression and decompression speed. LZ4 gives a slightly worse > compression ratio compared with LZO (and much worse than Zlib) > but compression speeds are *generally* similar to LZO. > Decompression tends to be much faster under LZ4 compared > with LZO hence it makes more sense to use LZ4 compression > when your workload involves a higher proportion of reads. > > The following patch set adds LZ4 compression support to BTRFS > using the existing kernel implementation. It is based on the > changeset for LZO support in 2011. Once a filesystem has been > mounted with LZ4 compression enabled older versions of BTRFS > will be unable to read it. This implementation is however > backwards compatible with filesystems that currently use > LZO or Zlib compression. Existing data will remain unchanged > but any new files that you create will be compressed with LZ4. > > Usage: > Apply the following 8 patches to the current git tree > (as of 20140531) and compile/load the btrfs module. > > # mount -t btrfs -o compress=lz4 device mountpoint > > or > > # mount -t btrfs -o compress-force=lz4 device mountpoint > I gave this patch-set a preliminary test, and there were no obvious signs of corruption. I was unable to run btrfsck or xfstests since btrfs-progs is not yet aware of lz4, so my testing should be considered superficial. One comment: IMHO, it would make sense to implement lz4 and lz4hc at the same time. Since both are now in the kernel, I assume we would go that direction eventually anyways, unless there are some wrinkles around lz4hc I don't fully appreciate. So we might as well conserve the kernel INCOMPAT flag.
next prev parent reply index Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-05-31 23:48 Philip Worrall 2014-05-31 23:48 ` [PATCH 1/8] Btrfs: Add kernel config options for LZ4 Philip Worrall 2014-05-31 23:48 ` [PATCH 2/8] Btrfs: Add lz4.c to the Makefile Philip Worrall 2014-05-31 23:48 ` [PATCH 3/8] Btrfs: Add lz4 compression to avaialble compression ops Philip Worrall 2014-05-31 23:48 ` [PATCH 4/8] Btrfs: Add definition for external lz4 compression struct Philip Worrall 2014-05-31 23:48 ` [PATCH 5/8] Btrfs: Add feature flags for LZ4 support Philip Worrall 2014-05-31 23:48 ` [PATCH 6/8] Btrfs: Ensure LZ4 feature flags are set when mounting with LZ4 Philip Worrall 2014-05-31 23:48 ` [PATCH 7/8] Btrfs: Add lz4 compression/decompression struct ops Philip Worrall 2014-05-31 23:48 ` [PATCH 8/8] Btrfs: Check for compress=lz4 in mount options Philip Worrall 2014-06-02 22:04 ` Mitch Harder [this message] 2014-06-03 15:53 ` [PATCH 0/8] Add support for LZ4 compression David Sterba 2014-06-04 14:00 ` Chris Mason 2014-06-12 8:47 ` David Sterba
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