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authorNeilBrown <neilb@suse.de>2007-05-09 05:35:38 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-09 15:30:57 -0400
commit08a02ecd28bad35a47357e611044dcbeab06e3d7 (patch)
tree31050d686e58d55411f95c89204321aa2ea2b63a /Documentation
parent42b9bebe3fea3d3ce381bc6735a3fb50e6613f06 (diff)
md: allow reshape_position for md arrays to be set via sysfs
"reshape_position" records how much progress has been made on a "reshape" (adding drives, changing layout or chunksize). When it is set, the number of drives, layout and chunksize can have two possible values, an old an a new. So allow these different values to be visible, and allow both old and new to be set: Set the old ones first, then the reshape_position, then the new values. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/md.txt72
1 files changed, 44 insertions, 28 deletions
diff --git a/Documentation/md.txt b/Documentation/md.txt
index 2202f5dc8ac2..5818628207b5 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -178,6 +178,21 @@ All md devices contain:
178 The size should be at least PAGE_SIZE (4k) and should be a power 178 The size should be at least PAGE_SIZE (4k) and should be a power
179 of 2. This can only be set while assembling an array 179 of 2. This can only be set while assembling an array
180 180
181 layout
182 The "layout" for the array for the particular level. This is
183 simply a number that is interpretted differently by different
184 levels. It can be written while assembling an array.
185
186 reshape_position
187 This is either "none" or a sector number within the devices of
188 the array where "reshape" is up to. If this is set, the three
189 attributes mentioned above (raid_disks, chunk_size, layout) can
190 potentially have 2 values, an old and a new value. If these
191 values differ, reading the attribute returns
192 new (old)
193 and writing will effect the 'new' value, leaving the 'old'
194 unchanged.
195
181 component_size 196 component_size
182 For arrays with data redundancy (i.e. not raid0, linear, faulty, 197 For arrays with data redundancy (i.e. not raid0, linear, faulty,
183 multipath), all components must be the same size - or at least 198 multipath), all components must be the same size - or at least
@@ -193,11 +208,6 @@ All md devices contain:
193 1.2 (newer format in varying locations) or "none" indicating that 208 1.2 (newer format in varying locations) or "none" indicating that
194 the kernel isn't managing metadata at all. 209 the kernel isn't managing metadata at all.
195 210
196 layout
197 The "layout" for the array for the particular level. This is
198 simply a number that is interpretted differently by different
199 levels. It can be written while assembling an array.
200
201 resync_start 211 resync_start
202 The point at which resync should start. If no resync is needed, 212 The point at which resync should start. If no resync is needed,
203 this will be a very large number. At array creation it will 213 this will be a very large number. At array creation it will
@@ -259,29 +269,6 @@ All md devices contain:
259 like active, but no writes have been seen for a while (safe_mode_delay). 269 like active, but no writes have been seen for a while (safe_mode_delay).
260 270
261 271
262 sync_speed_min
263 sync_speed_max
264 This are similar to /proc/sys/dev/raid/speed_limit_{min,max}
265 however they only apply to the particular array.
266 If no value has been written to these, of if the word 'system'
267 is written, then the system-wide value is used. If a value,
268 in kibibytes-per-second is written, then it is used.
269 When the files are read, they show the currently active value
270 followed by "(local)" or "(system)" depending on whether it is
271 a locally set or system-wide value.
272
273 sync_completed
274 This shows the number of sectors that have been completed of
275 whatever the current sync_action is, followed by the number of
276 sectors in total that could need to be processed. The two
277 numbers are separated by a '/' thus effectively showing one
278 value, a fraction of the process that is complete.
279
280 sync_speed
281 This shows the current actual speed, in K/sec, of the current
282 sync_action. It is averaged over the last 30 seconds.
283
284
285As component devices are added to an md array, they appear in the 'md' 272As component devices are added to an md array, they appear in the 'md'
286directory as new directories named 273directory as new directories named
287 dev-XXX 274 dev-XXX
@@ -412,6 +399,35 @@ also have
412 Note that the numbers are 'bit' numbers, not 'block' numbers. 399 Note that the numbers are 'bit' numbers, not 'block' numbers.
413 They should be scaled by the bitmap_chunksize. 400 They should be scaled by the bitmap_chunksize.
414 401
402 sync_speed_min
403 sync_speed_max
404 This are similar to /proc/sys/dev/raid/speed_limit_{min,max}
405 however they only apply to the particular array.
406 If no value has been written to these, of if the word 'system'
407 is written, then the system-wide value is used. If a value,
408 in kibibytes-per-second is written, then it is used.
409 When the files are read, they show the currently active value
410 followed by "(local)" or "(system)" depending on whether it is
411 a locally set or system-wide value.
412
413 sync_completed
414 This shows the number of sectors that have been completed of
415 whatever the current sync_action is, followed by the number of
416 sectors in total that could need to be processed. The two
417 numbers are separated by a '/' thus effectively showing one
418 value, a fraction of the process that is complete.
419
420 sync_speed
421 This shows the current actual speed, in K/sec, of the current
422 sync_action. It is averaged over the last 30 seconds.
423
424 suspend_lo
425 suspend_hi
426 The two values, given as numbers of sectors, indicate a range
427 within the array where IO will be blocked. This is currently
428 only supported for raid4/5/6.
429
430
415Each active md device may also have attributes specific to the 431Each active md device may also have attributes specific to the
416personality module that manages it. 432personality module that manages it.
417These are specific to the implementation of the module and could 433These are specific to the implementation of the module and could