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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-03 10:05:38 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-03 10:05:38 -0700 |
commit | e5021876c91dc3894b2174cca8fa797f8e29e7b9 (patch) | |
tree | cf6cc6591a8421e0f75cfcfbc10312421bd8e9f1 /Documentation/admin-guide | |
parent | 46f0537b1ecf672052007c97f102a7e6bf0791e4 (diff) | |
parent | e265eb3a30543a237b2ebc4e0422ac82e55b07e4 (diff) | |
download | linux-stable-e5021876c91dc3894b2174cca8fa797f8e29e7b9.tar.gz linux-stable-e5021876c91dc3894b2174cca8fa797f8e29e7b9.tar.bz2 linux-stable-e5021876c91dc3894b2174cca8fa797f8e29e7b9.zip |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md
Pull MD updates from Shaohua Li:
- Add Partial Parity Log (ppl) feature found in Intel IMSM raid array
by Artur Paszkiewicz. This feature is another way to close RAID5
writehole. The Linux implementation is also available for normal
RAID5 array if specific superblock bit is set.
- A number of md-cluser fixes and enabling md-cluster array resize from
Guoqing Jiang
- A bunch of patches from Ming Lei and Neil Brown to rewrite MD bio
handling related code. Now MD doesn't directly access bio bvec,
bi_phys_segments and uses modern bio API for bio split.
- Improve RAID5 IO pattern to improve performance for hard disk based
RAID5/6 from me.
- Several patches from Song Liu to speed up raid5-cache recovery and
allow raid5 cache feature disabling in runtime.
- Fix a performance regression in raid1 resync from Xiao Ni.
- Other cleanup and fixes from various people.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: (84 commits)
md/raid10: skip spare disk as 'first' disk
md/raid1: Use a new variable to count flighting sync requests
md: clear WantReplacement once disk is removed
md/raid1/10: remove unused queue
md: handle read-only member devices better.
md/raid10: wait up frozen array in handle_write_completed
uapi: fix linux/raid/md_p.h userspace compilation error
md-cluster: Fix a memleak in an error handling path
md: support disabling of create-on-open semantics.
md: allow creation of mdNNN arrays via md_mod/parameters/new_array
raid5-ppl: use a single mempool for ppl_io_unit and header_page
md/raid0: fix up bio splitting.
md/linear: improve bio splitting.
md/raid5: make chunk_aligned_read() split bios more cleanly.
md/raid10: simplify handle_read_error()
md/raid10: simplify the splitting of requests.
md/raid1: factor out flush_bio_list()
md/raid1: simplify handle_read_error().
Revert "block: introduce bio_copy_data_partial"
md/raid1: simplify alloc_behind_master_bio()
...
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r-- | Documentation/admin-guide/md.rst | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/Documentation/admin-guide/md.rst b/Documentation/admin-guide/md.rst index 1e61bf50595c..84de718f24a4 100644 --- a/Documentation/admin-guide/md.rst +++ b/Documentation/admin-guide/md.rst @@ -276,14 +276,14 @@ All md devices contain: array creation it will default to 0, though starting the array as ``clean`` will set it much larger. - new_dev + new_dev This file can be written but not read. The value written should be a block device number as major:minor. e.g. 8:0 This will cause that device to be attached to the array, if it is available. It will then appear at md/dev-XXX (depending on the name of the device) and further configuration is then possible. - safe_mode_delay + safe_mode_delay When an md array has seen no write requests for a certain period of time, it will be marked as ``clean``. When another write request arrives, the array is marked as ``dirty`` before the write @@ -292,7 +292,7 @@ All md devices contain: period as a number of seconds. The default is 200msec (0.200). Writing a value of 0 disables safemode. - array_state + array_state This file contains a single word which describes the current state of the array. In many cases, the state can be set by writing the word for the desired state, however some states @@ -401,7 +401,30 @@ All md devices contain: once the array becomes non-degraded, and this fact has been recorded in the metadata. + consistency_policy + This indicates how the array maintains consistency in case of unexpected + shutdown. It can be: + none + Array has no redundancy information, e.g. raid0, linear. + + resync + Full resync is performed and all redundancy is regenerated when the + array is started after unclean shutdown. + + bitmap + Resync assisted by a write-intent bitmap. + + journal + For raid4/5/6, journal device is used to log transactions and replay + after unclean shutdown. + + ppl + For raid5 only, Partial Parity Log is used to close the write hole and + eliminate resync. + + The accepted values when writing to this file are ``ppl`` and ``resync``, + used to enable and disable PPL. As component devices are added to an md array, they appear in the ``md`` @@ -563,6 +586,9 @@ Each directory contains: adds bad blocks without acknowledging them. This is largely for testing. + ppl_sector, ppl_size + Location and size (in sectors) of the space used for Partial Parity Log + on this device. An active md device will also contain an entry for each active device |