Bug 1301073 - DM_MULTIPATH_TIMESTAMP among udev properties when device is no longer multipathed
DM_MULTIPATH_TIMESTAMP among udev properties when device is no longer multipa...
Status: CLOSED NOTABUG
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: device-mapper-multipath (Show other bugs)
7.2
Unspecified Unspecified
unspecified Severity unspecified
: rc
: ---
Assigned To: LVM and device-mapper development team
Lin Li
:
Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2016-01-22 09:19 EST by mulhern
Modified: 2016-02-11 23:16 EST (History)
6 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Environment:
Last Closed: 2016-02-11 23:16:02 EST
Type: Bug
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


Attachments (Terms of Use)

  None (edit)
Description mulhern 2016-01-22 09:19:28 EST
Description of problem:

This value hangs around in a device's udev properties even when device is no longer multipathed. Other DM_MULTIPATH_* values disappear.

Version-Release number of selected component (if applicable):

Name        : device-mapper-multipath
Arch        : x86_64
Version     : 0.4.9
Release     : 85.el7
Size        : 178 k
Repo        : installed
From repo   : RHEL-7

How reproducible:

Seems consistent.

Steps to Reproduce:
1. Remove some multipath devices from a group.
2. Use udevadm to list their udev properties.
3. Notice that DM_MULTIPATH_TIMESTAMP remains even while other DM_MULTIPATH_* properties are gone.

Actual results:

DM_MULTIPATH_TIMESTAMP remains, other DM_MULTIPATH_* properties gone.

Expected results:

I was a little surprised to see any DM_MULTIPATH_* properties remaining for the device.

Additional info:

This may be quite deliberate, but even a reboot doesn't seem to clear it.
Comment 2 Ben Marzinski 2016-02-11 23:16:02 EST
DM_MULTIPATH_TIMESTAMP will always be there when multipathing is enabled and multipathd is running.  It's purpose it to cut down on how often multipath has to check if a device is a multipath path.  This can take a bit of time, so we don't want to check on every change event.  Instead, multipathd updates a timestamp whenever a new path device is discovered for the first time, or the configuration file is reloaded.  When a change event happens, the device checks its existing timestamp value against the current one, and if it has changed, multipath will recheck the path.

Note You need to log in before you can comment on or make changes to this bug.