path: root/Documentation
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authorDavid Sterba <>2016-08-17 19:33:24 +0200
committerDavid Sterba <>2016-08-17 20:00:00 +0200
commit87c1bd13c1fca430c3dbf0da62e9aa33bde609c8 (patch)
treead45775c8e908aa806e5db22314c3164abf7a348 /Documentation
parentbfecd8bd6aafd3be183506e4a351d412f39fc2bc (diff)
btrfs-progs: check: adjust command line options for the low-memory mode
Change the single-purpose option --low-memory to a generic option that takes the mode. Currently supported are the original mode and the low-memory in the same way. Signed-off-by: David Sterba <>
Diffstat (limited to 'Documentation')
1 files changed, 11 insertions, 4 deletions
diff --git a/Documentation/btrfs-check.asciidoc b/Documentation/btrfs-check.asciidoc
index 4e27863e..abc9f0dc 100644
--- a/Documentation/btrfs-check.asciidoc
+++ b/Documentation/btrfs-check.asciidoc
@@ -93,11 +93,18 @@ build the extent tree from scratch
NOTE: Do not use unless you know what you're doing.
-check fs in low memory usage mode(experimental)
-May takes longer time than normal check.
+select mode of operation regarding memory and IO
-NOTE: Doesn't work with '--repair' option yet.
+The 'MODE' can be one of 'original' and 'lowmem'. The original mode is mostly
+unoptimized regarding memory consumpption and can lead to out-of-memory
+conditions on large filesystems. The possible workaround is to export the block
+device over network to a machine with enough memory. The low memory mode is
+supposed to address the memory consumption, at the cost of increased IO when it
+needs to re-read blocks when needed. This may increase run time.
+NOTE: 'lowmem' mode does not work with '--repair' yet, and is still considered