** Description changed:
+ [Impact]
+ This affects users of multipath systems where devices may be slow to be
detected. (See below).
+
+ On some systems disks may be slow to be detected due to a number of
+ reasons: slow disks, spin delay, large number of devices to scan, etc.
+ If the disk containing the root filesystem fails to be detected/scanned
+ when the multipath initramfs scripts are run, the system will give up
+ and fail to load the rootfs, which results in a failure to boot (and the
+ user will be thrown into a busybox shell in the initramfs).
+
+ [Test case]
+ Boot the system.
+
+ [Regression Potential]
+ Given that this changes the load order for the system, it may cause some
delay in booting due to the extra time taken to load all maps for the rootfs to
become available through multipath. Also, crashes in multipathd may now affect
early boot.
+
+ ---
+
Canonical FYI:
We appear to have a regression in the current 14.04 environment back to
the behavior originally outlined in Comment #10 of LP Bug 1429327.
---Problem---
A multipath install of 14.04.04 fails to create the install mpath
device on subsequent boots. While the root filesystem ends up being
mounted on top of one of the path devices, other partitions on that
multipath device will not be automatically found.
---Additional details---
For one example host, the install disk was set up with a root and
swap partition:
Dec 14 21:37:55 disk-detect: create: mpath0 (35000c5007655a10f) undef IBM
,ST300MP0064
Dec 14 21:37:55 disk-detect: size=279G features='0' hwhandler='0' wp=undef
Dec 14 21:37:55 disk-detect: |-+- policy='round-robin 0' prio=1 status=undef
Dec 14 21:37:55 disk-detect: | `- 0:0:7:0 sdc 8:32 undef ready running
Dec 14 21:37:55 disk-detect: `-+- policy='round-robin 0' prio=1 status=undef
Dec 14 21:37:55 disk-detect: `- 1:0:3:0 sdd 8:48 undef ready running
The resulting fstab entries after install were:
/dev/mapper/mpath0-part2 / ext4 errors=remount-ro 0 1
/dev/mapper/mpath0-part3 none swap sw 0 0
In post-install boots, the multipath command appears to be executed
prior to any disks being discovered:
Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... [ 0.612955] ipr: IBM Power RAID SCSI
Device Driver version: 2.6.1 (March 12, 2015)
[ 0.612985] ipr 0000:80:00.0: Found IOA with IRQ: 0
[ 0.613478] ipr 0000:80:00.0: ibm,query-pe-dma-windows(53) 800000 8000000
20000164 returned 0
Begin: Running /scripts/local-top ... [ 0.613727] ipr 0000:80:00.0:
ibm,create-pe-dma-window(54) 800000 8000000 20000164 10 21 returned 0 (liobn =
0x70000164 starting addr = 8000000 0)
Begin: Loading multipath modules ... [ 0.618790] device-mapper: multipath:
version 1.9.0 loaded
Success: loaded module dm-multipath.
Failure: failed to load module dm-emc.
done.
Begin: Waiting for scsi storage ... done.
Begin: Discovering multipaths ... [ 0.623429] be2net 0002:01:00.0: be2net
version is 10.6.0.2
[ 0.623587] be2net 0002:01:00.0: enabling device (0000 -> 0002)
done.
[ 0.636785] ipr 0000:80:00.0: Using 64-bit direct DMA at offset
800000000000000
[ 0.637343] be2net 0002:01:00.0: PCIe error reporting enabled
[ 0.641435] ipr 0000:80:00.0: Received IRQ : 20
[ 0.641522] ipr 0000:80:00.0: Request for 2 MSIXs succeeded.
[ 0.645713] ipr 0000:80:00.0: Starting IOA initialization sequence.
[ 0.645719] scsi host0: IBM 0 Storage Adapter
[ 0.645741] ipr 0000:80:00.0: Starting IOA initialization sequence.
[ 0.645833] ipr 0001:a0:00.0: Found IOA with IRQ: 0
[ 0.646221] ipr 0000:80:00.0: Adapter firmware version: 13510C00
[ 0.647673] ipr 0000:80:00.0: IOA initialized.
[ 0.648009] ipr 0001:a0:00.0: Received IRQ : 448
[ 0.648041] ipr 0001:a0:00.0: Request for 2 MSIXs succeeded.
[ 0.651764] ipr 0001:a0:00.0: Starting IOA initialization sequence.
[ 0.651769] scsi host1: IBM 0 Storage Adapter
[ 0.651795] ipr 0001:a0:00.0: Starting IOA initialization sequence.
[ 0.652262] ipr 0001:a0:00.0: Adapter firmware version: 13510C00
[ 0.653702] ipr 0001:a0:00.0: IOA initialized.
[ 0.660800] scsi 0:3:0:0: No Device IBM 57B1001SISIOA 0150
PQ: 0 ANSI: 0
[ 0.660811] scsi 0:3:0:0: Resource path: 0/FE
[ 0.672518] scsi 0:0:0:0: Direct-Access IBM ST300MP0064 7D0E
PQ: 0 ANSI: 6
[ 0.672530] scsi 0:0:0:0: Resource path: 0/00-0E-08
...
(first device in mpath0 seen at this point):
[ 0.710988] scsi 1:0:3:0: Direct-Access IBM ST300MP0064 7D0E
PQ
: 0 ANSI: 6
[ 0.710994] scsi 1:0:3:0: Resource path: 1/00-0E-0A
The system ends up mounting the root filesystem from /dev/sdc2,
and the post-mount run of multipath errors out creating mpath0:
[ 10.056286] device-mapper: table: 252:0: multipath: error getting device
[ 10.082644] device-mapper: table: 252:0: multipath: error getting device
[ 10.192614] device-mapper: table: 252:2: multipath: error getting device
[ 10.222609] device-mapper: table: 252:2: multipath: error getting device
[ 10.663458] device-mapper: table: 252:2: multipath: error getting device
[ 10.682690] device-mapper: table: 252:2: multipath: error getting device
[ 10.796743] device-mapper: table: 252:2: multipath: error getting device
Since no other filesystems depend on mpath0 for this example config,
the system is able to boot, but lacks swap due to the missing swap
device.
** Changed in: multipath-tools (Ubuntu Trusty)
Status: New => Incomplete
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https://bugs.launchpad.net/bugs/1526984
Title:
ISST-LTE: root mpath device unavailable after installation
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