Bug 956750 - vdsm is reporting negative values for available memory
Summary: vdsm is reporting negative values for available memory
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Virtualization Manager
Classification: Red Hat
Component: ovirt-engine
Version: 3.2.0
Hardware: Unspecified
OS: Unspecified
unspecified
high
Target Milestone: ---
: 3.3.0
Assignee: Doron Fediuck
QA Contact: Lukas Svaty
URL:
Whiteboard: sla
: 966165 1049859 (view as bug list)
Depends On:
Blocks: 977758 982245 982639
TreeView+ depends on / blocked
 
Reported: 2013-04-25 14:29 UTC by Ido Begun
Modified: 2018-12-05 15:57 UTC (History)
18 users (show)

Fixed In Version: is6
Doc Type: Bug Fix
Doc Text:
Clone Of:
: 977758 982245 (view as bug list)
Environment:
Last Closed: 2013-06-04 10:26:23 UTC
oVirt Team: SLA
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
vdsm.log (842.36 KB, text/x-log)
2013-04-25 14:29 UTC, Ido Begun 		no flags Details
View All


Links
System ID Private Priority Status Summary Last Updated
Red Hat Knowledge Base (Solution) 290883 0 None None None Never
oVirt gerrit 15328 0 None None None Never
oVirt gerrit 16253 0 None None None Never
oVirt gerrit 16256 0 None None None Never

Description Ido Begun 2013-04-25 14:29:56 UTC 
Created attachment 739934 [details]
vdsm.log

Description of problem:
VDSM is reporting negative values for available memory.

Version-Release number of selected component (if applicable):
vdsm-4.10.2-15.0

How reproducible:
100%

Steps to Reproduce:
1. Run memory load on host
2. vdsClient -s 0 getVdsStats | grep memAvailable
  
Actual results:
VDSM reports negative values ( memAvailable = -818 )

Expected results:
VDSM should never report negative values for available memory
Comment 1 Doron Fediuck 2013-06-03 12:04:09 UTC 
*** Bug 966165 has been marked as a duplicate of this bug. ***
Comment 2 Saveliev Peter 2013-06-04 10:26:23 UTC 
The current memory computation is accurate and takes into account memory overcommitment. That's why one can get negative values there even if there is no KSM running.

Maybe it should be mentioned in the docs — then open docs issue, please. But it is not a bug.
Comment 3 Oded Ramraz 2013-06-05 09:29:29 UTC 
Peter , can we show 0 instead of negative number? 
Showing negative numbers as for available memory has bad user experience / impact.
Comment 4 Saveliev Peter 2013-06-05 09:45:12 UTC 
Technically speaking, we can show anything. Yes, we can split one value into two: available memory (from 0 to N) and memory overcommitment (from -N to -1).

But since this particular value is used only in the engine, it is better to keep current behaviour:

1. users are not supposed to do anything with VDSM ←→ engine protocol
2. the engine can rely on this values

vdsClient is written to be used by experienced administrators and developers, so it is better to mention this particular case in the project documentation, 'cause it can be confusing.
Comment 5 Michal Skrivanek 2013-06-05 09:58:27 UTC 
I second the suggestion to keep showing negative values and provide an explanation in docs.
Comment 6 Doron Fediuck 2013-06-10 16:00:05 UTC 
Re-opening on the engine as this is creating false events in the system.
Additionally, the existing logic in the system should be verified in this light.
Comment 7 ofri 2013-06-23 07:45:33 UTC 
After discussion: This bug will require both change in VDSM and engine. 
VDSM currently does not report the true free memory on the host. instead it reports the total memory minus the sum of all used memory (for all processes).
VDSM should report true free mem on host. this data should be the one referenced by the engine in context of 'minimum memory' events.
Comment 12 Itamar Heim 2014-01-21 22:28:52 UTC 
Closing - RHEV 3.3 Released
Comment 13 Itamar Heim 2014-01-21 22:28:52 UTC 
Closing - RHEV 3.3 Released
Comment 14 Itamar Heim 2014-01-21 22:31:52 UTC 
Closing - RHEV 3.3 Released
Comment 15 Jiri Moskovcak 2014-02-24 15:16:32 UTC 
*** Bug 1049859 has been marked as a duplicate of this bug. ***
Note You need to log in before you can comment on or make changes to this bug.