[SERVER-16459] Unexpectedly high non-mapped virtual memory usage on secondary Created: 08/Dec/14  Updated: 21/Dec/14  Resolved: 11/Dec/14

Status: Closed
Project: Core Server
Component/s: Diagnostics
Affects Version/s: 2.8.0-rc2
Fix Version/s: None

Type: Bug Priority: Major - P3
Reporter: John Morales Assignee: Ramon Fernandez Marina
Resolution: Duplicate Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File Screen Shot 2014-12-08 at 2.47.33 PM.png    
Issue Links:
Duplicate
duplicates SERVER-16515 MMAPv1 should have a singleton Record... Closed
Related
Operating System: ALL
Participants:

 Description   

Upon upgrading a secondary from 2.6.3 to 2.8.0rc2 mmapv1, MMS began reporting a consistent large increase in non-mapped virtual memory usage: from ~1.2GB to ~19.4GB (screenshot attached).

MMS defines non-mapped virtual memory as:
(serverStatus.mem.virtual - 2 * serverStatus.mem.mapped)

The 2x is applied because journalling is enabled. (And was enabled both before and after the upgrade.)

Open connections reported by this host also remained the same before and after the upgrade.

For easy reference, below is the serverStatus.mem section of this host's last ping:

        "mem": {
            "virtual": 576484,
            "bits": 64,
            "supported": true,
            "mappedWithJournal": 556650,
            "mapped": 278325,
            "resident": 34019
        },
 
# MMS' calculation:
# (576484 - (2 * 278325))/1024 => ~19.4GB


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