Agree, looks like disk caching, which is considered in use but can be freed as things ask for it. What kind of storage are you using here?

I checked my converged group, the GUI memory use looks like it includes the cache as well, just not as extreme as yours :) If you wanted to confirm, you could clear it with

sync; echo 3 > /proc/sys/vm/drop_caches

and you should get all the cache memory back without rebooting. Presumably, it’s all holding filesystem data for quick access, so not a terrible thing, just alarming to see 97% utilization. Unless it kicked off unneeded MOM runs if you’re using same page merging and ballooning, then its doing unneeded work and maybe slowing your VMs… You’d probably see it in top if this was the case, it’s fairly CPU intensive.

Ultimately, you may want to file a bug/feature request to have the GUI differentiate cache from “regular’ in use memory for clarity.

On Dec 13, 2018, at 12:06 AM, Tony Brian Albers <tba@kb.dk> wrote:

Screenshots attached

We have 2 hosts and 24 running vms, all vms are pretty small.

As you can see, top and the dashboard does not agree.

An interesting thing is that if I view the host itself in the engine,
it says under "General" that 
Max free Memory for scheduling new VMs: 413360 MB

So maybe it's some sort of caching that's using the memory.


/tony

On Wed, 2018-12-12 at 09:59 -0600, Darrell Budic wrote:
Yeah, you’re right about 400G, I dropped a digit reading it out of
your top display. 

So what are you seeing in the dashboard, I’m not sure I understand
the disconnect between the top you shared and what you’re seeing
there. It shows lots more than 110G in use, I gather? Or are you
seeing this on the hosts page per host mem use?

On Dec 12, 2018, at 12:34 AM, Tony Brian Albers <tba@kb.dk> wrote:

I'm not following you on the 42G available, the way I see it
there's
400+G available:

[root@man-001 ~]# free -h
              total        used        free      shared  buff/cache
   a
vailable
Mem:           503G         96G         19G        205M        387G
    
    405G
Swap:          4.0G        520K        4.0G

And here's top sorted by %mem usage:

top - 07:29:00 up 104 days, 20:56,  1 user,  load average: 0.59,
0.68,
0.67
Tasks: 564 total,   1 running, 563 sleeping,   0 stopped,   0
zombie
%Cpu(s):  1.5 us,  0.2 sy,  0.0 ni, 98.2 id,  0.0 wa,  0.0 hi,  0.0
si,  0.0 st
KiB Mem : 52807689+total, 20085144 free, 10132981+used,
40666195+buff/cache
KiB Swap:  4194300 total,  4193780 free,      520 used.
42491062+avail
Mem 

   PID USER      PR  NI    VIRT    RES    SHR S  %CPU
%MEM     TIME+
COMMAND                                     
  5517 qemu      20   0 9128268   8.1g  14084
S   3.0  1.6   5892:07
qemu-kvm                                    
 14187 qemu      20   0 9210236   8.1g  14072
S   5.3  1.6   6586:00
qemu-kvm                                    
 12791 qemu      20   0 9272448   8.1g  14140
S  14.2  1.6  17452:10
qemu-kvm                                    
135526 qemu      20   0 9117748   8.1g  13664
S   2.3  1.6   5874:48
qemu-kvm                                    
  7938 qemu      20   0 9129936   8.1g  13744
S   2.3  1.6  22109:28
qemu-kvm                                    
 11764 qemu      20   0 9275520   8.1g  13720
S   3.3  1.6  10679:25
qemu-kvm                                    
 12066 qemu      20   0 9360552   8.1g  13708
S   3.0  1.6  10724:34
qemu-kvm                                    
 11153 qemu      20   0 9113544   8.1g  13700
S  15.6  1.6  19050:12
qemu-kvm                                    
 12436 qemu      20   0 9161800   8.1g  13712
S  16.2  1.6  21268:00
qemu-kvm                                    
  6902 qemu      20   0 9110480   8.0g  13580
S   0.7  1.6   1804:16
qemu-kvm                                    
  7621 qemu      20   0 9203816   4.8g  14264
S   1.7  1.0   3143:35
qemu-kvm                                    
  6587 qemu      20   0 4880980   4.1g  13744
S   0.7  0.8   2354:56
qemu-kvm                                    
  7249 qemu      20   0 4913084   1.6g  13712
S   0.7  0.3   1380:38
qemu-kvm                                    
111877 qemu      20   0 1911088   1.1g  14076 S   0.3  0.2
419:58.70
qemu-kvm                                    
  4602 vdsm       0 -20 4803160 114184  13860
S   1.3  0.0   2143:44
vdsmd                                       
  4058 root      15  -5 1154020  38804   9588
S   0.0  0.0   0:00.81
supervdsmd                                  
   818 root      20   0   84576  35356  34940
S   0.0  0.0   1:05.60
systemd-journal                             
  3602 root      20   0 1496796  32536   9232 S   0.0  0.0
123:53.70
python                                      
  2672 root      20   0  358328  30228   7984
S   0.0  0.0   0:14.76
firewalld                                   
  4801 vdsm      20   0 1640996  28904   5484
S   0.0  0.0   1265:14
python


Rebooting a host doesn't help, (I've tried that earlier) the only
thing
that works is to stop all vm's, reboot all hosts at the same time
and
start vm's again. Then memory usage shown in the dashboard slowly
increases over time again.

/tony






On Tue, 2018-12-11 at 14:09 -0600, Darrell Budic wrote:
That’s only reporting 42G available of your 512, ok but something
still using it. Try sorting the top by memory %, should be ‘>’
while
it’s running.

On Dec 11, 2018, at 1:39 AM, Tony Brian Albers <tba@kb.dk>
wrote:

Looks ok to me:

top - 08:38:07 up 103 days, 22:05,  1 user,  load average:
0.68,
0.62,
0.57
Tasks: 565 total,   1 running, 564 sleeping,   0 stopped,   0
zombie
%Cpu(s):  1.0 us,  0.5 sy,  0.0 ni, 98.5 id,  0.0 wa,  0.0
hi,  0.0
si,  0.0 st
KiB Mem : 52807689+total, 22355988 free, 10132873+used,
40439219+buff/cache
KiB Swap:  4194300 total,  4193780 free,      520 used.
42492028+avail
Mem 

   PID USER      PR  NI    VIRT    RES    SHR S  %CPU
%MEM     TIME+
COMMAND                  
 14187 qemu      20   0 9144668   8.1g  14072
S  12.6  1.6   6506:46
qemu-kvm                 
 11153 qemu      20   0 9244680   8.1g  13700
S   4.3  1.6  18881:11
qemu-kvm                 
 12436 qemu      20   0 9292936   8.1g  13712
S   3.3  1.6  21071:56
qemu-kvm                 
  5517 qemu      20   0 9128268   8.1g  14084
S   3.0  1.6   5801:03
qemu-kvm                 
 11764 qemu      20   0 9185364   8.1g  13720
S   3.0  1.6  10585:14
qemu-kvm                 
  7938 qemu      20   0 9252876   8.1g  13744
S   2.6  1.6  21912:46
qemu-kvm                 
 12791 qemu      20   0 9182292   8.1g  14140
S   2.6  1.6  17299:36
qemu-kvm                 
  4602 vdsm       0 -20 4803160 <tel:20%204803160>
114132  13860
S   2.3  0.0   2123:45
vdsmd                    
  7621 qemu      20   0 9187424   4.8g  14264
S   2.3  1.0   3114:25
qemu-kvm                 
 12066 qemu      20   0 9188436   8.1g  13708
S   2.3  1.6  10629:53
qemu-kvm                 
135526 qemu      20   0 9298060   8.1g  13664
S   2.0  1.6   5792:05
qemu-kvm                 
  6587 qemu      20   0 4883036   4.1g  13744
S   1.3  0.8   2334:54
qemu-kvm                 
  3814 root      20   0 1450200 <tel:1450200>  25096  14208
S   1.0  0.0 368:03.80
libvirtd                 
  6902 qemu      20   0 9110480   8.0g  13580
S   1.0  1.6   1787:57
qemu-kvm                 
  7249 qemu      20   0 4913084   1.6g  13712
S   0.7  0.3   1367:32
qemu-kvm                 


It looks like it's only in oVirt-engine that there's an issue.
The
host
seems happy enough.

/tony



On Mon, 2018-12-10 at 20:14 -0600, Darrell Budic wrote:
Grab a shell on your hosts and check top memory use quick.
Could
be
VDSMD, in which case restarting the process will give you a
temp
fix.
If you’re running hyperconvered, check your gluster version,
there
was a leak in versions 3.12.7 - 3.1.12 or so, updating
ovirt/gluster
is the best fix for that.

On Dec 10, 2018, at 7:36 AM, Tony Brian Albers <tba@kb.dk>
wrote:

Hi guys,

We have a small test installation here running around 30
vms on
2
hosts.

oVirt 4.2.5.3

The hosts each have 512 GB memory, and the vms are sized
with
4-8
GB
each.

I have noticed that over the last months, the memory usage
in
the
dashboard has been increasing and is now showing 946.8 GB
used
of
1007.2 GB.

What can be causing this?

TIA,

-- 
-- 
Tony Albers
Systems Architect
Systems Director, National Cultural Heritage Cluster
Royal Danish Library, Victor Albecks Vej 1, 8000 Aarhus C,
Denmark.
Tel: +45 2566 2383 / +45 8946 2316
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-- 
Tony Albers
Systems Architect
Systems Director, National Cultural Heritage Cluster
Royal Danish Library, Victor Albecks Vej 1, 8000 Aarhus C,
Denmark.
Tel: +45 2566 2383 <tel:+45%202566%202383> / +45 8946 2316
<tel:+45%208946%202316>

-- 
-- 
Tony Albers
Systems Architect
Systems Director, National Cultural Heritage Cluster
Royal Danish Library, Victor Albecks Vej 1, 8000 Aarhus C, Denmark.
Tel: +45 2566 2383 / +45 8946 2316


-- 
Tony Albers
Systems Architect
Systems Director, National Cultural Heritage Cluster
Royal Danish Library, Victor Albecks Vej 1, 8000 Aarhus C, Denmark.
Tel: +45 2566 2383 / +45 8946 2316<2018-12-13-070032_349x526_scrot.png><2018-12-13-070259_504x81_scrot.png>