Hi,
These are mdadm patches to support cache layer in raid 5/6. Shaohua
has sent the kernel patch earlier with subject "a caching layer
for raid 5/6".
These patches add write cache support for the following commands:
mdadm --detail
mdadm --create
mdadm --assemble
mdadm --incremental
mdadm --examine
mdadm --zero-super
Cache device is assigned with dev_role 0xFFFD (where 0xFFFF is for
spare and 0xFFFE is for failed). Note that there is compatibility
issue that older mdadm will show cache device as spare in --detail:
Number Major Minor RaidDevice State
0 8 32 0 active sync /dev/sdc
1 8 48 1 active sync /dev/sdd
2 8 64 2 active sync /dev/sde
3 8 80 3 active sync /dev/sdf
4 8 17 - spare /dev/sdb1
Also, older mdadm will show cache device as "Active device 65533"
in --examine:
Device Role : Active device 65533
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
Song Liu (7):
Show device as cache in --detail
Enable create array with write cache (--write-cache DEVICE).
Create write-cache superblock in mdadm --create
Assemble array with writecache
Check write cache in incremental
Zero write-cache superblock in --zero-super
Add information about write-cache superblock to --examine
Assemble.c | 52 +++++++++++++----
Create.c | 21 +++++--
Detail.c | 3 +-
Examine.c | 29 +++++++++-
Incremental.c | 37 ++++++++++--
Kill.c | 19 ++++++
ReadMe.c | 1 +
md_p.h | 74 ++++++++++++++++++++++++
mdadm.c | 19 ++++++
mdadm.h | 11 +++-
super1.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
util.c | 3 +-
12 files changed, 422 insertions(+), 29 deletions(-)
--
1.8.1
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