diff --git a/Documentation/btrfs-quota.asciidoc b/Documentation/btrfs-quota.asciidoc index 71602fbf..33c3bfd7 100644 --- a/Documentation/btrfs-quota.asciidoc +++ b/Documentation/btrfs-quota.asciidoc @@ -16,7 +16,23 @@ of a btrfs filesystem. The quota groups (qgroups) are managed by the subcommand `btrfs qgroup`(8). NOTE: the qgroups are different than the traditional user quotas and designed -to track shared and exlusive data per-subvolume. +to track shared and exlusive data per-subvolume. Plese refer to the section +'HIERARCHICAL QUOTA GROUP CONCEPTS' for a detailed description. + +PERFORMANCE IMPLICATIONS +~~~~~~~~~~~~~~~~~~~~~~~~ + +When the quotas are turned on, they affect all extent processing, taking a +performance hit. It is not recommended to turn on qgroups unless the user +intends to actually use them. + +STABILITY STATUS +~~~~~~~~~~~~~~~~ + +The qgroup implementation has turned out to be quite difficult as it affects +the core of the filesystem operation. The users have hit various corner cases +over time, eg. wrong accounting or system instability. The situation is +gradually improving but currently (4.7) there are still issues found and fixed. HIERARCHICAL QUOTA GROUP CONCEPTS ---------------------------------