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mdadm/0040-mdadm-md.4-add-the-descriptions-for-bitmap-sysfs-nod.patch
Neil Brown 2e35d7583b Accepting request 781064 from home:colyli:branches:Base:System
- Update for latest mdadm-4.1+ patches, this is required by
  jsc#SLE-10078 and jsc#SLE-9348. Mostly the purpose is for
  latest Intel IMSM raid support.
  The following patches also include previous patches with
  new re-ordered prefix numbers.
- Makefile: install mdadm_env.sh to /usr/lib/mdadm (bsc#1111960)
  0000-Makefile-install-mdadm_env.sh-to-usr-lib-mdadm.patch
- Assemble: keep MD_DISK_FAILFAST and MD_DISK_WRITEMOSTLY flag
  (jsc#SLE-10078, jsc#SLE-9348)
  0001-Assemble-keep-MD_DISK_FAILFAST-and-MD_DISK_WRITEMOST.patch
- Document PART-POLICY lines (jsc#SLE-10078, jsc#SLE-9348)
  0002-Document-PART-POLICY-lines.patc
- policy: support devices with multiple paths.
  (jsc#SLE-10078, jsc#SLE-9348)
  0003-policy-support-devices-with-multiple-paths.patch
- mdcheck: add systemd unit files to run mdcheck. (bsc#1115407)
  0004-mdcheck-add-systemd-unit-files-to-run-mdcheck.patch
- Monitor: add system timer to run --oneshot periodically (bsc#1115407)
  0005-Monitor-add-system-timer-to-run-oneshot-periodically.patch
- imsm: update metadata correctly while raid10 double
  (jsc#SLE-10078, jsc#SLE-9348)
  0006-imsm-update-metadata-correctly-while-raid10-double-d.patch
- Assemble: mask FAILFAST and WRITEMOSTLY flags when finding
  (jsc#SLE-10078, jsc#SLE-9348)
  0007-Assemble-mask-FAILFAST-and-WRITEMOSTLY-flags-when-fi.patch
- Grow: avoid overflow in compute_backup_blocks()
  (jsc#SLE-10078, jsc#SLE-9348)
  0008-Grow-avoid-overflow-in-compute_backup_blocks.patch
- Grow: report correct new chunk size. (jsc#SLE-10078, jsc#SLE-9348)
  0009-Grow-report-correct-new-chunk-size.patch

OBS-URL: https://build.opensuse.org/request/show/781064
OBS-URL: https://build.opensuse.org/package/show/Base:System/mdadm?expand=0&rev=181
2020-03-04 04:49:18 +00:00

104 lines
3.8 KiB
Diff

From e53cb968691d9e40d83caf5570da3bb7b83c64e1 Mon Sep 17 00:00:00 2001
From: Guoqing Jiang <gqjiang@suse.com>
Date: Fri, 31 May 2019 10:10:00 +0800
Subject: [PATCH] mdadm/md.4: add the descriptions for bitmap sysfs nodes
Git-commit: e53cb968691d9e40d83caf5570da3bb7b83c64e1
Patch-mainline: mdadm-4.1+
References: jsc#SLE-10078, jsc#SLE-9348
The sysfs nodes under bitmap are not recorded in md.4,
add them based on md.rst and kernel source code.
Cc: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
Signed-off-by: Coly Li <colyli@suse.de>
---
md.4 | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 69 insertions(+)
diff --git a/md.4 b/md.4
index 3a1d677..e86707a 100644
--- a/md.4
+++ b/md.4
@@ -1101,6 +1101,75 @@ stripe that requires some "prereading". For fairness this defaults to
maximizes sequential-write throughput at the cost of fairness to threads
doing small or random writes.
+.TP
+.B md/bitmap/backlog
+The value stored in the file only has any effect on RAID1 when write-mostly
+devices are active, and write requests to those devices are proceed in the
+background.
+
+This variable sets a limit on the number of concurrent background writes,
+the valid values are 0 to 16383, 0 means that write-behind is not allowed,
+while any other number means it can happen. If there are more write requests
+than the number, new writes will by synchronous.
+
+.TP
+.B md/bitmap/can_clear
+This is for externally managed bitmaps, where the kernel writes the bitmap
+itself, but metadata describing the bitmap is managed by mdmon or similar.
+
+When the array is degraded, bits mustn't be cleared. When the array becomes
+optimal again, bit can be cleared, but first the metadata needs to record
+the current event count. So md sets this to 'false' and notifies mdmon,
+then mdmon updates the metadata and writes 'true'.
+
+There is no code in mdmon to actually do this, so maybe it doesn't even
+work.
+
+.TP
+.B md/bitmap/chunksize
+The bitmap chunksize can only be changed when no bitmap is active, and
+the value should be power of 2 and at least 512.
+
+.TP
+.B md/bitmap/location
+This indicates where the write-intent bitmap for the array is stored.
+It can be "none" or "file" or a signed offset from the array metadata
+- measured in sectors. You cannot set a file by writing here - that can
+only be done with the SET_BITMAP_FILE ioctl.
+
+Write 'none' to 'bitmap/location' will clear bitmap, and the previous
+location value must be write to it to restore bitmap.
+
+.TP
+.B md/bitmap/max_backlog_used
+This keeps track of the maximum number of concurrent write-behind requests
+for an md array, writing any value to this file will clear it.
+
+.TP
+.B md/bitmap/metadata
+This can be 'internal' or 'clustered' or 'external'. 'internal' is set
+by default, which means the metadata for bitmap is stored in the first 256
+bytes of the bitmap space. 'clustered' means separate bitmap metadata are
+used for each cluster node. 'external' means that bitmap metadata is managed
+externally to the kernel.
+
+.TP
+.B md/bitmap/space
+This shows the space (in sectors) which is available at md/bitmap/location,
+and allows the kernel to know when it is safe to resize the bitmap to match
+a resized array. It should big enough to contain the total bytes in the bitmap.
+
+For 1.0 metadata, assume we can use up to the superblock if before, else
+to 4K beyond superblock. For other metadata versions, assume no change is
+possible.
+
+.TP
+.B md/bitmap/time_base
+This shows the time (in seconds) between disk flushes, and is used to looking
+for bits in the bitmap to be cleared.
+
+The default value is 5 seconds, and it should be an unsigned long value.
+
.SS KERNEL PARAMETERS
The md driver recognised several different kernel parameters.
--
2.25.0