path: root/Documentation
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authorQu Wenruo <>2014-04-11 10:43:52 +0800
committerDavid Sterba <>2014-04-22 14:15:24 +0200
commit5dbedcc3e01949ae4095714871346509f9c4624d (patch)
tree7e2b9d347b798fb021e8b89b6eb6cddae0f910e1 /Documentation
parent7151a86539275e5ed8bc20b7a033a69a24b6ae3d (diff)
btrfs-progs: Add device management related paragraph.
Add device management related paragraph to better explain btrfs device management. Cc: Marc MERLIN <> Signed-off-by: Qu Wenruo <> Signed-off-by: David Sterba <>
Diffstat (limited to 'Documentation')
3 files changed, 52 insertions, 0 deletions
diff --git a/Documentation/btrfs-balance.txt b/Documentation/btrfs-balance.txt
index 2289fdfb..1b1861cf 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.
@@ -75,3 +77,4 @@ further details.
diff --git a/Documentation/btrfs-device.txt b/Documentation/btrfs-device.txt
index 20d7bcd7..523ae4de 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.
+Btrfs filesystem is capable to manage multiple devices.
+Btrfs filesystem uses different profiles to manage different RAID level, and
+use balance to rebuild chunks, also devices can be added/removed/replace
+Btrfs filesystem uses 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.
+`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.
'add' [-Kf] <dev> [<dev>...] <path>::
@@ -73,3 +113,5 @@ further details.
diff --git a/Documentation/btrfs-replace.txt b/Documentation/btrfs-replace.txt
index 8c5dcc4f..0d3b3185 100644
--- a/Documentation/btrfs-replace.txt
+++ b/Documentation/btrfs-replace.txt
@@ -13,6 +13,12 @@ DESCRIPTION
'btrfs replace' is used to replace btrfs managed devices with other device.
+Note: this is not currently supported for RAID5/6 profiles and must use the
+device add/delete workaround.
+It is recommended to see `btrfs-device`(8) for more details about btrfs device
'start' [-Bfr] <srcdev>|<devid> <targetdev> <path>::
@@ -74,3 +80,4 @@ further details.