No Free SWAP Memory PA-450

[Hamid.Saffarzadeh]

Hi guys,

We have a firewall that shows the free SWAP memory 0. Is this normal? It is a new installation and Genindex process seems to be normal. Here is the output of "show system resources":

admin@PA-450> show system resources 

top - 09:49:41 up 21 days, 20:55,  1 user,  load average: 1.96, 2.03, 2.07
Tasks: 238 total,   1 running, 165 sleeping,   0 stopped,   1 zombie
%Cpu(s): 11.9 us, 10.4 sy,  2.2 ni, 74.8 id,  0.0 wa,  0.7 hi,  0.0 si,  0.0 st
KiB Mem : 16269716 total,   925460 free,  5240044 used, 10104212 buff/cache
KiB Swap:     1020 total,        0 free,     1020 used.  6868148 avail Mem 

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
 5937       20   0 1789300 385796  38960 S  25.0  2.4 118:03.32 configd
 3564        0 -20 3848148   3.4g   3.3g S  18.8 21.7  93:13.92 masterd_ap+
 7148       20   0  131.6g   3.3g   3.3g S  18.8 21.4   4648:05 pan_task
24419       20   0  156148  20156  10672 S  18.8  0.1   0:00.09 masterd_ba+
 7150       20   0  131.6g   3.3g   3.3g S  12.5 21.4   1587:13 pan_task
 3582       15  -5  173524  13904   7920 S   6.2  0.1  72:14.64 sysd
 6235       20   0  716664 101468  32564 S   6.2  0.6 161:27.25 dnsproxyd
 5162       20   0 1183668  36384  26768 S   0.0  0.2   4:35.71 sysdagent
 5167       30  10  142456  22560   8628 S   0.0  0.1   1:51.01 core_gdb
 5179       20   0    7144   1796   1648 S   0.0  0.0   0:00.00 mcelog
 5318       20   0  630396  32664  25408 S   0.0  0.2   3:25.44 chasd
 5323       20   0  602820  73484  30784 S   0.0  0.5   2:33.35 dagger
 5327       30  10  335308  32284  11456 S   0.0  0.2  58:14.72 python
 5331       20   0  545184  34644  27076 S   0.0  0.2  96:41.78 contentd
 5358       20   0  328820   9468   8112 S   0.0  0.1   1:36.91 plugin_api+
 5449       10 -10  128.6g  14112  11328 S   0.0  0.1 235:50.39 brdagent
 5774       20   0   97356   9036   7768 S   0.0  0.1   2:59.44 ehmon
 5891       20   0  707300  39724  28892 S   0.0  0.2   2:53.88 cryptod
 5915       20   0   38188   5196   4716 S   0.0  0.0   0:00.00 sshd
 5930       20   0 1870336 553008 151900 S   0.0  3.4  63:22.54 devsrvr
 5945       20   0  477692  68176  31132 S   0.0  0.4 125:47.07 distributo+
 5948       20   0  521600  89120  31316 S   0.0  0.5  28:26.67 iotd
 5950       20   0 1045776 207192  35860 S   0.0  1.3  25:53.63 reportd
 5952       20   0  741968 215668 145800 S   0.0  1.3 224:46.63 useridd
 6024       20   0  602052 142424  31840 S   0.0  0.9  11:34.05 mgmtsrvr
 6048 nobody    20   0   50280   4008   3020 S   0.0  0.0  27:15.12 redis-serv+
 6073 nobody    20   0   52840   4348   3148 S   0.0  0.0 100:16.26 redis-serv+
 6101 nobody    20   0   50280   4164   3076 S   0.0  0.0  26:05.48 redis-serv+
 6142 nobody    20   0  574108  50868  36036 S   0.0  0.3   2:21.95 httpd
 6145       20   0 1175176  66648   8632 S   0.0  0.4  95:27.58 identitycl+
 6171       20   0 1001624  16620   5216 S   0.0  0.1  59:57.53 dsclient
 6210       20   0  650968  41692  30364 S   0.0  0.3   3:23.76 ikemgr
 6213       20   0 1697164 312584  49328 S   0.0  1.9   2155:52 logrcvr
 6215       20   0  812372  37840  27892 S   0.0  0.2   2:39.18 rasmgr
 6216       20   0  653392  36004  26632 S   0.0  0.2   3:11.46 keymgr
 6218       20   0  278428  34340  26716 S   0.0  0.2   1:41.94 pan_ifmgr
 6219       20   0 2711508  98396  32008 S   0.0  0.6  13:35.15 varrcvr
 6223       17  -3  560940  35568  27396 S   0.0  0.2  10:59.88 l2ctrld
 6224       17  -3  280116  34952  26472 S   0.0  0.2   2:36.77 ha_agent
 6225       20   0  538356  49188  29860 S   0.0  0.3   4:28.46 satd
 6231       20   0 1093900  43776  29972 S   0.0  0.3   3:33.18 sslmgr
 6234       20   0  557208  34688  27012 S   0.0  0.2   2:51.82 pan_dhcpd
 6238       20   0  488312  35340  26816 S   0.0  0.2   2:14.85 pppoed
 6240       17  -3  979544  57424  30656 S   0.0  0.4   7:10.50 routed
 6241       20   0  471164  56576  34884 S   0.0  0.3  20:56.38 authd
 7143       20   0  131.5g   3.3g   3.3g S   0.0 21.4   6:57.56 sdwand
 7144       20   0  131.4g   3.3g   3.3g S   0.0 21.4  38:53.51 pan_dha
 7145       20   0  131.4g   3.3g   3.3g S   0.0 21.4   7:10.32 mprelay
 7146       20   0  132.5g   3.5g   3.3g S   0.0 22.7  63:32.92 pan_comm
 7147       20   0  131.5g   3.3g   3.3g S   0.0 21.4  21:59.79 tund
 7152       20   0  263764  49484   5092 S   0.0  0.3  38:43.76 wifclient
 7160       30  10  163000  26704  11144 S   0.0  0.2  11:47.02 python

[LAYER_8 · Accepted solution]

Quick way to calculate real time memory use here. (Note that the swap available portion is actually free memory, see more here.) Are you seeing MGT server performance degradation? 

I won't say it's normal but I've seen it from time to time. The kernel leaves a certain minimum amount of physical memory free for certain situations so we would expect to see this.

Whenever swapped out pages are needed back in RAM, cache reduces and pages are moved back from swap to RAM leading to swap getting reduced.

It is normal for linux like OSes (like PAN-OS) to keep the memory in buffer/cache and make it available only when it is needed. I do not see any reason yet to believe that the device is reaching capacity or a reboot is required.

To dig deeper in cached memory you can look at the output of memory_detail in the mp-monitor. Definitions of all the terms in memory_detail can be found here:
https://man7.org/linux/man-pages/man5/proc.5.html

[jasonwald]

Noticing the same thing on 10.1.5H1. I installed 10.1.6 a few days ago and so far it has not re-occurred. This is happening on PA-440's.

[PavelK]

Hello @Hamid.Saffarzadeh @jasonwald 

what you are observing is expected in PA-400 series Firewalls. Please check this KB.

Kind Regards

Pavel