Merge branch 'release' of git://lm-sensors.org/kernel/mhoffman/hwmon-2.6

[pandora-kernel.git] / Documentation / md.txt

diff --git a/Documentation/md.txt b/Documentation/md.txt
index 396cdd9..1da9d1b 100644 (file)
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -236,6 +236,11 @@ All md devices contain:
      writing the word for the desired state, however some states
      cannot be explicitly set, and some transitions are not allowed.
 
      writing the word for the desired state, however some states
      cannot be explicitly set, and some transitions are not allowed.
 

+     Select/poll works on this file.  All changes except between
+       active_idle and active (which can be frequent and are not
+       very interesting) are notified.  active->active_idle is
+       reported if the metadata is externally managed.
+

      clear
          No devices, no size, no level
          Writing is equivalent to STOP_ARRAY ioctl
      clear
          No devices, no size, no level
          Writing is equivalent to STOP_ARRAY ioctl


@@ -292,6 +297,10 @@ Each directory contains:
              writemostly - device will only be subject to read
                         requests if there are no other options.
                         This applies only to raid1 arrays.
              writemostly - device will only be subject to read
                         requests if there are no other options.
                         This applies only to raid1 arrays.

+             blocked  - device has failed, metadata is "external",
+                        and the failure hasn't been acknowledged yet.
+                        Writes that would write to this device if
+                        it were not faulty are blocked.

              spare    - device is working, but not a full member.
                         This includes spares that are in the process
                         of being recovered to
              spare    - device is working, but not a full member.
                         This includes spares that are in the process
                         of being recovered to


@@ -301,6 +310,12 @@ Each directory contains:
        Writing "remove" removes the device from the array.
        Writing "writemostly" sets the writemostly flag.
        Writing "-writemostly" clears the writemostly flag.
        Writing "remove" removes the device from the array.
        Writing "writemostly" sets the writemostly flag.
        Writing "-writemostly" clears the writemostly flag.

+       Writing "blocked" sets the "blocked" flag.
+       Writing "-blocked" clear the "blocked" flag and allows writes
+               to complete.
+
+       This file responds to select/poll. Any change to 'faulty'
+       or 'blocked' causes an event.

 
       errors
        An approximate count of read errors that have been detected on
 
       errors
        An approximate count of read errors that have been detected on


@@ -332,7 +347,7 @@ Each directory contains:
         for storage of data.  This will normally be the same as the
        component_size.  This can be written while assembling an
         array.  If a value less than the current component_size is
         for storage of data.  This will normally be the same as the
        component_size.  This can be written while assembling an
         array.  If a value less than the current component_size is

-        written, component_size will be reduced to this value.
+        written, it will be rejected.

 
 
 An active md device will also contain and entry for each active device
 
 
 An active md device will also contain and entry for each active device


@@ -381,6 +396,19 @@ also have
        'check' and 'repair' will start the appropriate process
            providing the current state is 'idle'.
 
        'check' and 'repair' will start the appropriate process
            providing the current state is 'idle'.
 

+      This file responds to select/poll.  Any important change in the value
+      triggers a poll event.  Sometimes the value will briefly be
+      "recover" if a recovery seems to be needed, but cannot be
+      achieved. In that case, the transition to "recover" isn't
+      notified, but the transition away is.
+
+   degraded
+      This contains a count of the number of devices by which the
+      arrays is degraded.  So an optimal array with show '0'.  A
+      single failed/missing drive will show '1', etc.
+      This file responds to select/poll, any increase or decrease
+      in the count of missing devices will trigger an event.
+

    mismatch_count
       When performing 'check' and 'repair', and possibly when
       performing 'resync', md will count the number of errors that are
    mismatch_count
       When performing 'check' and 'repair', and possibly when
       performing 'resync', md will count the number of errors that are


@@ -450,3 +478,9 @@ These currently include
       there are upper and lower limits (32768, 16).  Default is 128.
   strip_cache_active (currently raid5 only)
       number of active entries in the stripe cache
       there are upper and lower limits (32768, 16).  Default is 128.
   strip_cache_active (currently raid5 only)
       number of active entries in the stripe cache

+  preread_bypass_threshold (currently raid5 only)
+      number of times a stripe requiring preread will be bypassed by
+      a stripe that does not require preread.  For fairness defaults
+      to 1.  Setting this to 0 disables bypass accounting and
+      requires preread stripes to wait until all full-width stripe-
+      writes are complete.  Valid values are 0 to stripe_cache_size.