From 5dbedcc3e01949ae4095714871346509f9c4624d Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 11 Apr 2014 10:43:52 +0800 Subject: [PATCH] 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 --- Documentation/btrfs-balance.txt | 3 +++ Documentation/btrfs-device.txt | 42 +++++++++++++++++++++++++++++++++ Documentation/btrfs-replace.txt | 7 ++++++ 3 files changed, 52 insertions(+) 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. + SUBCOMMAND ---------- :: @@ -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 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. +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 +online. + +Profile:: +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. + +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] [...] :: @@ -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 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 +management. + SUBCOMMAND ---------- 'start' [-Bfr] | :: @@ -74,3 +80,4 @@ further details. SEE ALSO -------- `mkfs.btrfs`(8), +`btrfs-device`(8),