Hi all,
the aim of this patch set is to issue a warning when a mixed profiles
filesystem is detected. This happens when the filesystems contains
(i.e.) raid1c3 and single chunk for data.
BTRFS has the capability to support a filesystem with mixed profiles.
However this could lead to an unexpected behavior when a new chunk is
allocated (i.e. the chunk profile is not what is wanted). Moreover
if the user is not aware of this, he could assume a redundancy which
doesn't exist (for example because there is some 'single' chunk when
it is expected the filesystem to be full raid1).
A possible cause of a mixed profiles filesystem is an interrupted
balance operation or a not fully balance due to very specific filter.
The check is added to the following btrfs commands:
- btrfs balance pause
- btrfs balance cancel
- btrfs filesystem usage
- btrfs device add
Suggestion about which commands should (not) have this check are
welcome.
v1
- first issue
v2
- add some needed missing pieces about raid1c[34]
- add the check to more btrfs commands
Example of output:
$ sudo ./btrfs fi us /tmp/t/
WARNING: cannot read detailed chunk info, per-device usage will not be shown, run as root
Overall:
Device size: 30.00GiB
Device allocated: 7.78GiB
Device unallocated: 22.22GiB
Device missing: 0.00B
Used: 1.94GiB
Free (estimated): 11.89GiB (min: 9.77GiB)
Data ratio: 2.33
Metadata ratio: 1.50
Global reserve: 3.25MiB (used: 0.00B)
Data,single: Size:1.00GiB, Used:973.87MiB (95.10%)
Data,RAID1C3: Size:2.00GiB, Used:178.98MiB (8.74%)
Metadata,single: Size:256.00MiB, Used:94.69MiB (36.99%)
Metadata,RAID1: Size:256.00MiB, Used:188.45MiB (73.61%)
System,single: Size:32.00MiB, Used:16.00KiB (0.05%)
WARNING: ------------------------------------------------------
WARNING: Detection of multiple profiles for a block group type:
WARNING:
WARNING: * DATA -> [raid1c3, single]
WARNING: * METADATA -> [raid1, single]
WARNING:
WARNING: Please consider using 'btrfs balance ...' commands set
WARNING: to solve this issue.
WARNING: ------------------------------------------------------
In this case there are two kind of chunks for data (raid1c3 and single)
and metadata (raid1, single).
Patch #1 and #2 are preparatory ones.
Patch #3 contains the code for the check.
Patch #4 adds the check to the command 'btrfs fi us'
Comments are welcome
BR
G.Baroncelli
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