FC Multipath may leave residual paths due to race condition
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| | os-brick |
Undecided
|
Gorka Eguileor | ||
Bug Description
When using FC multipath we may end up with residual paths that should have been removed but due to a race condition they are recreated and left there.
This can create problems if the storage controller reuses the same WWID.
The race condition occurs between the removal of a SCSI device and the connection of a volume and is due to our scanning parameters being too broad (we use - - -, which means any HBA channel, any SCSI target, and any LUN).
Example of the race between 2 VMs hosted in the same compute node:
1. A1(Create LUN):WWID X assigned
2. A2(Scan LUN):Detected sda-WWID X
3. ...
4. R1(Delete path):sda removed
5.
6.
7. R2(Remove LUN):Remove WWID X
So we'll end up having /dev/sda when it shouldn't.
| Changed in os-brick: | |
| assignee: | nobody → Gorka Eguileor (gorka) |
| Changed in os-brick: | |
| status: | New → In Progress |
| description: | updated |
| description: | updated |
| description: | updated |
| description: | updated |
| Yafei Yu (yu-yafei) wrote : | #2 |
ISCSI Multipath may leave residual paths too.
Reviewed: https:/
Committed: https:/
Submitter: Jenkins
Branch: master
commit 28a4d55a0a465ac
Author: Gorka Eguileor <email address hidden>
Date: Wed Jul 27 14:06:06 2016 +0200
Fix FC multipath rescan
Fiber Chanel multipath rescan uses wildcards for the host rescan, which
can end up recreating devices that had just been removed if there's a
race condition between the removal of a SCSI device and the connection
of a volume.
The race condition happens if a rescan done when attaching happens right
between us removing the path and removing the lun, because the rescan
will add not only the new path we are attaching, but the old path we are
removing, since the lun still hasn't been removed.
This would leave orphaned devices that pollute our environment and will
be recognized as down paths when the storage controller reuses the same
WWID.
This patch narrows the rescan to only rescan for the specific lun
number, and if possible it also filters the rescan by HBA channel and
SCSI target ID.
We only filter by HBA channel and SCSI target ID when we can find this
information, and that is when the FC storage servers implement a single
WWNN for all ports.
Change-Id: Id6ed98d3fb8b4b
Closes-Bug: #1608614
| Changed in os-brick: | |
| status: | In Progress → Fix Released |
Fix proposed to branch: stable/mitaka
Review: https:/
Change abandoned by Gorka Eguileor (<email address hidden>) on branch: stable/mitaka
Review: https:/
Reason: No backports on the os-brick library
This issue was fixed in the openstack/os-brick 1.6.0 release.
| OpenStack Infra (hudson-openstack) wrote : | #7 |
This issue was fixed in the openstack/os-brick 1.6.0 release.
Change abandoned by Gorka Eguileor (<email address hidden>) on branch: stable/mitaka
Review: https:/
Reason: No love from community :'-(
Fix proposed to branch: master
Review: https:/