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authorEric Dillmann <[email protected]>2013-01-23 10:54:30 +0100
committerBrian Behlendorf <[email protected]>2013-01-29 09:28:20 -0800
commit9759c60f1a1503e48dc5c45a209c3edd5758319f (patch)
treead56536c5e57c831f38f4b0df81f816470f28c1c /man/man8
parentff5b1c8065c8a43add534892172f0aa5aba90f3d (diff)
Illumos #3035 LZ4 compression support in ZFS and GRUB
3035 LZ4 compression support in ZFS and GRUB Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Christopher Siden <[email protected]> Reviewed by: George Wilson <[email protected]> Approved by: Christopher Siden <[email protected]> References: illumos/illumos-gate@a6f561b4aee75d0d028e7b36b151c8ed8a86bc76 https://www.illumos.org/issues/3035 http://wiki.illumos.org/display/illumos/LZ4+Compression+In+ZFS This patch has been slightly modified from the upstream Illumos version to be compatible with Linux. Due to the very limited stack space in the kernel a lz4 workspace kmem cache is used. Since we are using gcc we are also able to take advantage of the gcc optimized __builtin_ctz functions. Support for GRUB has been dropped from this patch. That code is available but those changes will need to made to the upstream GRUB package. Lastly, several hunks of dead code were dropped for clarity. They include the functions real_LZ4_uncompress(), LZ4_compressBound() and the Visual Studio specific hunks wrapped in _MSC_VER. Ported-by: Eric Dillmann <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #1217
Diffstat (limited to 'man/man8')
-rw-r--r--man/man8/zfs.811
1 files changed, 10 insertions, 1 deletions
diff --git a/man/man8/zfs.8 b/man/man8/zfs.8
index 38d54c9cb..474fde97a 100644
--- a/man/man8/zfs.8
+++ b/man/man8/zfs.8
@@ -25,6 +25,7 @@
.\" Copyright (c) 2012 by Delphix. All rights reserved.
.\" Copyright (c) 2012, Joyent, Inc. All rights reserved.
.\" Copyright 2012 Nexenta Systems, Inc. All Rights Reserved.
+.\" Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
.\"
.TH zfs 8 "Jan 10, 2013" "ZFS pool 28, filesystem 5" "System Administration Commands"
.SH NAME
@@ -731,7 +732,7 @@ Changing this property affects only newly-written data.
.ne 2
.mk
.na
-\fBcompression\fR=\fBon\fR | \fBoff\fR | \fBlzjb\fR | \fBgzip\fR | \fBgzip-\fR\fIN\fR | \fBzle\fR
+\fBcompression\fR=\fBon\fR | \fBoff\fR | \fBlzjb\fR | \fBgzip\fR | \fBgzip-\fR\fIN\fR | \fBzle\fR | \fBlz4\fR
.ad
.sp .6
.RS 4n
@@ -741,6 +742,14 @@ The \fBgzip\fR compression algorithm uses the same compression as the \fBgzip\fR
.sp
The \fBzle\fR (zero-length encoding) compression algorithm is a fast and simple algorithm to eliminate runs of zeroes.
.sp
+The \fBlz4\fR compression algorithm is a high-performance replacement
+for the \fBlzjb\fR algorithm. It features significantly faster
+compression and decompression, as well as a moderately higher
+compression ratio than \fBlzjb\fR, but can only be used on pools with
+the \fBlz4_compress\fR feature set to \fIenabled\fR. See
+\fBzpool-features\fR(5) for details on ZFS feature flags and the
+\fBlz4_compress\fR feature.
+.sp
This property can also be referred to by its shortened column name \fBcompress\fR. Changing this property affects only newly-written data.
.RE