Add device management related paragraph to better explain btrfs device management.
Cc: Marc MERLIN <m...@merlins.org> Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com> --- Documentation/btrfs-balance.txt | 3 +++ Documentation/btrfs-device.txt | 42 +++++++++++++++++++++++++++++++++++++++++ Documentation/btrfs-replace.txt | 4 ++++ 3 files changed, 49 insertions(+) diff --git a/Documentation/btrfs-balance.txt b/Documentation/btrfs-balance.txt index 2289fdf..1b1861c 100644 --- a/Documentation/btrfs-balance.txt +++ b/Documentation/btrfs-balance.txt @@ -14,6 +14,8 @@ DESCRIPTION 'btrfs balance' is used to balance chunks in a btrfs filesystem across multiple or even single device. +See `btrfs-device`(8) for more details about the effect on device management. + SUBCOMMAND ---------- <path>:: @@ -75,3 +77,4 @@ further details. SEE ALSO -------- `mkfs.btrfs`(8), +`btrfs-device`(8) diff --git a/Documentation/btrfs-device.txt b/Documentation/btrfs-device.txt index 20d7bcd..474d411 100644 --- a/Documentation/btrfs-device.txt +++ b/Documentation/btrfs-device.txt @@ -14,6 +14,46 @@ DESCRIPTION 'btrfs device' is used to control the btrfs devices, since btrfs can be used across several devices, 'btrfs device' is used for multiple device management. +DEVICE MANAGEMENT +----------------- +Btrfs filesystem is capable to manage multiple devices. + +Btrfs filesystem use different profiles to manage different RAID level, and +use balance to rebuild chunks, also devices can be added/removed/replace +online. + +Profile:: +Btrfs filesystem use data/metadata profiles to manage allocation/duplication +mechanism. Profiles like RAID level can be assigned to data and metadata separately. ++ +See `mkfs.btrfs`(8) for more details. + +RAID level:: +Btrfs filesystem supports most of the standard RAID level: 0/1/5/6/10. +RAID levels can be assigned at mkfs time or online. ++ +See `mkfs.btrfs`(8) for mkfs time RAID level assign and `btrfs-balance`(8) for +online RAID level assign. + +Balance:: +`btrfs-balance`(8) subcommand can be used to balance or rebuild chunks to the +desired profile. ++ +Due to the fact that balance can rebuild/recovery chunks according to its RAID +duplication if possible, so when using RAID1/5/6/10 with some devices failed +and you just added a new device to btrfs using `btrfs-device`(8), you should +run `btrfs-balance`(8) to rebuild the chunks. ++ +See `btrfs-balance`(8) for more details. + +Device add/remove/replace:: +Device can be added/removed using `btrfs-replace`(8) subcommand and replaced +using `btrfs-replace`(8). ++ +When device is removed or replaced, btrfs will do the chunk rebuild if needed. ++ +See `btrfs-replace`(8) and this man page for more details. + SUBCOMMAND ---------- 'add' [-Kf] <dev> [<dev>...] <path>:: @@ -73,3 +113,5 @@ further details. SEE ALSO -------- `mkfs.btrfs`(8), +`btrfs-replace`(8), +`btrfs-balance`(8) diff --git a/Documentation/btrfs-replace.txt b/Documentation/btrfs-replace.txt index 8c5dcc4..15a46c2 100644 --- a/Documentation/btrfs-replace.txt +++ b/Documentation/btrfs-replace.txt @@ -13,6 +13,9 @@ DESCRIPTION ----------- 'btrfs replace' is used to replace btrfs managed devices with other device. +It is recommended to see `btrfs-device`(8) for more details about btrfs device +management. + SUBCOMMAND ---------- 'start' [-Bfr] <srcdev>|<devid> <targetdev> <path>:: @@ -74,3 +77,4 @@ further details. SEE ALSO -------- `mkfs.btrfs`(8), +`btrfs-device`(8), -- 1.9.2 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
