When a path is lost and then reinstated later, the ALUA
device handler will not pick up this change and continue
to possibly provide incorrect (stale) information about
its ALUA state to the 'sysfs' prioritizer if the path's
priorities were changed prior to the loss of those paths.
On the loss of an I_T nexus, the path state should not
continue to use its last known state. Many things and a lot
of time could have passed between the path loss and its
eventual reinstatemnt.
The ALUA device handler didn't have this issue since it
always got the ALUA state from the target by sending an RTPG
request on the path and updated the priority. However with
the detect priority set to true by default, the 'sysfs'
prioritzier will be used on targets that support ALUA rather
than the 'alua' prioritizer.
Without re-evaluating the ALUA state when a path returns
multipath is left with path states which do not reflect
the actual ALUA states the target is providing.
3624a9370f0f545fc7c3e46a100011010 dm-2 PURE,FlashArray
size=3.0T features='0' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 13:0:0:1 sdg 8:96 active ready running
| |- 12:0:0:1 sdf 8:80 active ready running
| |- 9:0:0:1 sdc 8:32 active ready running
| `- 1:0:0:1 sdb 8:16 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
|- 14:0:0:1 sdh 8:112 active ready running
|- 15:0:0:1 sdi 8:128 active ready running
|- 10:0:0:1 sdd 8:48 active ready running
`- 11:0:0:1 sde 8:64 active ready running
# sg_rtpg /dev/sdh (Active/Optimized)
target port group asymmetric access state : 0x00
Signed-off-by: Brian Bunker <brian@xxxxxxxxxxxxxxx>
Signed-off-by: Seamus Connor <sconnor@xxxxxxxxxxxxxxx>
---
multipathd/main.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/multipathd/main.c b/multipathd/main.c
index 230c9d10..dd48be74 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -1937,6 +1937,11 @@ reinstate_path (struct path * pp)
else {
condlog(2, "%s: reinstated", pp->dev_t);
update_queue_mode_add_path(pp->mpp);
+ if (strcmp(pp->prio.name, PRIO_SYSFS) == 0) {
+ condlog(2, "%s: rescan target to update priorities",
+ pp->dev_t);
+ rescan_path(pp->udev);
+ }
}
}
--
2.43.0
