** Description changed:
- TBD - will update soon the LP with details, for now it's just for the LP
- number.
+ [Impact]
+
+ * Currently, mounted raid0/md-linear arrays have no indication/warning
+ when one or more members are removed or suffer from some non-recoverable
+ error condition. The mdadm tool shows "clean" state regardless if a
+ member was removed.
+
+ * The patch proposed in this SRU addresses this issue by introducing a
+ new state "broken", which is analog to "clean" but indicates that array
+ is not in a good/correct state. The commit, available upstream as
+ 43ebc910 ("mdadm: Introduce new array state 'broken' for raid0/linear")
+ [0], was extensively discussed and received a good amount of
+ reviews/analysis by both the current mdadm maintainer as well as an old
+ maintainer.
+
+ * One important note here is that this patch requires a counter-part in the kernel to be fully functional, which was SRUed in LP: #1847773.
+ It works fine/transparently without this kernel counter-part though.
+
+ [Test case]
+
+ * To test this patch, create a raid0 or linear md array on Linux using
+ mdadm, like: "mdadm --create md0 --level=0 --raid-devices=2 /dev/nvme0n1
+ /dev/nvme1n1";
+
+ * Format the array using a FS of your choice (for example ext4) and
+ mount the array;
+
+ * Remove one member of the array, for example using sysfs interface (for
+ nvme: echo 1 > /sys/block/nvme0n1/device/device/remove, for scsi: echo 1
+ > /sys/block/sdX/device/delete);
+
+ * Without this patch, the array state shown by "mdadm --detail" is
+ "clean", regardless a member is missing/failed.
+
+ [Regression potential]
+
+ * There's not much potential regression here; we just exhibit arrays'
+ state as "broken" if they have one or more missing/failed members; we
+ believe the most common "issue" that could be reported from this patch
+ is if an userspace tool rely on the array status as being always "clean"
+ even for broken devices, then such tool may behave differently with this
+ patch.
+
+ * Note that we *proactively* skipped Xenial SRU here, in order to
+ prevent potential regressions - Xenial mdadm tool lacks code
+ infrastructure used by this patch, so the decision was for
+ safety/stability, by only SRUing Bionic / Disco / Eoan mdadm versions.
+
+ [0]
+ https://git.kernel.org/pub/scm/utils/mdadm/mdadm.git/commit/?id=43ebc910
** Also affects: mdadm (Ubuntu Eoan)
Importance: Medium
Assignee: Guilherme G. Piccoli (gpiccoli)
Status: Confirmed
** Also affects: mdadm (Ubuntu Disco)
Importance: Undecided
Status: New
** Also affects: mdadm (Ubuntu Bionic)
Importance: Undecided
Status: New
** Changed in: mdadm (Ubuntu Bionic)
Status: New => Confirmed
** Changed in: mdadm (Ubuntu Disco)
Status: New => Confirmed
** Changed in: mdadm (Ubuntu Bionic)
Importance: Undecided => Medium
** Changed in: mdadm (Ubuntu Disco)
Importance: Undecided => Medium
** Changed in: mdadm (Ubuntu Disco)
Assignee: (unassigned) => Guilherme G. Piccoli (gpiccoli)
** Changed in: mdadm (Ubuntu Bionic)
Assignee: (unassigned) => Guilherme G. Piccoli (gpiccoli)
** Patch added: "lp-1847924-bionic.debdiff"
https://bugs.launchpad.net/ubuntu/+source/mdadm/+bug/1847924/+attachment/5296836/+files/lp-1847924-bionic.debdiff
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https://bugs.launchpad.net/bugs/1847924
Title:
Introduce broken state parsing to mdadm
Status in mdadm package in Ubuntu:
Confirmed
Status in mdadm source package in Bionic:
Confirmed
Status in mdadm source package in Disco:
Confirmed
Status in mdadm source package in Eoan:
Confirmed
Bug description:
[Impact]
* Currently, mounted raid0/md-linear arrays have no indication/warning
when one or more members are removed or suffer from some non-
recoverable error condition. The mdadm tool shows "clean" state
regardless if a member was removed.
* The patch proposed in this SRU addresses this issue by introducing a
new state "broken", which is analog to "clean" but indicates that
array is not in a good/correct state. The commit, available upstream
as 43ebc910 ("mdadm: Introduce new array state 'broken' for
raid0/linear") [0], was extensively discussed and received a good
amount of reviews/analysis by both the current mdadm maintainer as
well as an old maintainer.
* One important note here is that this patch requires a counter-part in the kernel to be fully functional, which was SRUed in LP: #1847773.
It works fine/transparently without this kernel counter-part though.
[Test case]
* To test this patch, create a raid0 or linear md array on Linux using
mdadm, like: "mdadm --create md0 --level=0 --raid-devices=2
/dev/nvme0n1 /dev/nvme1n1";
* Format the array using a FS of your choice (for example ext4) and
mount the array;
* Remove one member of the array, for example using sysfs interface
(for nvme: echo 1 > /sys/block/nvme0n1/device/device/remove, for scsi:
echo 1 > /sys/block/sdX/device/delete);
* Without this patch, the array state shown by "mdadm --detail" is
"clean", regardless a member is missing/failed.
[Regression potential]
* There's not much potential regression here; we just exhibit arrays'
state as "broken" if they have one or more missing/failed members; we
believe the most common "issue" that could be reported from this patch
is if an userspace tool rely on the array status as being always
"clean" even for broken devices, then such tool may behave differently
with this patch.
* Note that we *proactively* skipped Xenial SRU here, in order to
prevent potential regressions - Xenial mdadm tool lacks code
infrastructure used by this patch, so the decision was for
safety/stability, by only SRUing Bionic / Disco / Eoan mdadm versions.
[0]
https://git.kernel.org/pub/scm/utils/mdadm/mdadm.git/commit/?id=43ebc910
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