From 4a1d07e8c3ae610c863e57ee31e1484d652367ea Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 31 Mar 2017 19:40:05 +0200 Subject: [PATCH] btrfs-progs: docs: mount options, enhance ssd/nossd Reported-by: Hans van Kranenburg Signed-off-by: David Sterba --- Documentation/btrfs-man5.asciidoc | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/Documentation/btrfs-man5.asciidoc b/Documentation/btrfs-man5.asciidoc index c8ef1c9..fe3cb92 100644 --- a/Documentation/btrfs-man5.asciidoc +++ b/Documentation/btrfs-man5.asciidoc @@ -348,19 +348,20 @@ If a version is not explicitly specified, the default implementation will be chosen, which is 'v1' as of 4.9. *ssd*:: -*nossd*:: *ssd_spread*:: +*nossd*:: (default: SSD autodetected) + Options to control SSD allocation schemes. By default, BTRFS will enable or disable SSD allocation heuristics depending on whether a -rotational or non-rotational disk is in use (contents of -'/sys/block/DEV/queue/rotational'). The 'ssd' and 'nossd' options -can override this autodetection. +rotational or non-rotational device is in use (contents of +'/sys/block/DEV/queue/rotational'). If it is, the 'ssd' option is turned on. +The option 'nossd' will disable the autodetection. + The 'ssd_spread' mount option attempts to allocate into bigger and aligned chunks of unused space, and may perform better on low-end SSDs. 'ssd_spread' -implies 'ssd', enabling all other SSD heuristics as well. +implies 'ssd', enabling all other SSD heuristics as well. The option 'nossd' +will disable all SSD options. *subvol='path'*:: Mount subvolume from 'path' rather than the toplevel subvolume. The -- 2.7.4