path: root/Documentation/btrfs-man5.asciidoc
diff options
authorDavid Sterba <>2017-03-31 19:40:05 +0200
committerDavid Sterba <>2017-03-31 19:40:05 +0200
commit4a1d07e8c3ae610c863e57ee31e1484d652367ea (patch)
tree11a7f9a41a494f8ff2ac2bd2b05c6aa9508addb9 /Documentation/btrfs-man5.asciidoc
parentbd0ab27afbf14370f9f0da1f5f5ecbb0adc654c1 (diff)
btrfs-progs: docs: mount options, enhance ssd/nossd
Reported-by: Hans van Kranenburg <> Signed-off-by: David Sterba <>
Diffstat (limited to 'Documentation/btrfs-man5.asciidoc')
1 files changed, 6 insertions, 5 deletions
diff --git a/Documentation/btrfs-man5.asciidoc b/Documentation/btrfs-man5.asciidoc
index c8ef1c96..fe3cb92a 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.
(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.
Mount subvolume from 'path' rather than the toplevel subvolume. The