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SHARED AND CACHED MEMORY FULL
Hi All,
I just install additional S5248F-ON switch to be in VLT with the existing switch. After the installation, the network monitoring system (Orion) show that the "Cached and shared Memory" of the switch are full. I have searched for documentation pertaining to this issue but am afraid I found known. I have not seen this on any of the other model currently in production. I will appreciate your help.
DELL-Chris H
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May 10th, 2024 20:14
Haryortheyji,
I haven't seen that issue before, but I do know that the memory used for buffers and cache (Buff/Cache) is considered as "available" memory. File System Operations, Program Execution-loading programs and its dependencies to improve execution speed, Caching of frequently accessed data ,are some legitimate actions resulting in increase in Buff/Cache.
The Operating System is expected to manage the memory resources efficiently. As a result, any available memory not actively used by applications or the operating system itself is utilized as buffer/cache memory. When applications or the operating system need more memory for active processes, the buffer/cache memory can quickly be released to accommodate these needs.
Now what I would suggest is that you verify if both switches are filling up. What you can do is run the command free -h and top utility to view Free memory, Buffered memory and Cache memory. That way you can confirm where the switch is sitting and rule out that it isn't an issue with the monitoring tool.
Let me know what you see.
shuff12
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May 10th, 2024 21:10
It could be due to a memory leak triggered by specific switch commands used for monitoring. This problem has been identified in certain firmware versions and does not affect all switch models. To resolve this, ensure your switch firmware is updated to a version that addresses this memory leak issue, such as xDoctor 4.8-86.1 or later, which includes changes to prevent higher memory usage and adds memory utilization alerting. If the problem persists after updating, it may be necessary to review the specific commands and configurations used in your network setup.
see https://www.dell.com/support/kbdoc/en-us/000205040/ecs-xdoctor-rap152-one-or-more-switches-have-low-available-memory?lang=en
haryortheyji
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May 10th, 2024 22:53
Thanks guys. this is the output from both switches. But I would appreciate a better understanding of this output:
SWITCH--A
top - 22:31:23 up 2 days, 7:06, 1 user, load average: 0.46, 0.54, 0.60
Tasks: 281 total, 1 running, 280 sleeping, 0 stopped, 0 zombie
%Cpu(s): 7.0 us, 7.0 sy, 0.0 ni, 84.5 id, 0.0 wa, 0.0 hi, 1.4 si, 0.0 st
KiB Mem : 16366144 total, 12907460 free, 2641188 used, 817496 buff/cache
KiB Swap: 1636612 total, 1636612 free, 0 used. 13419220 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1979 root 20 0 2969232 380060 118236 S 11.8 2.3 244:24.70 base_nas
1059 root 20 0 3244992 68408 35388 S 5.9 0.4 262:06.44 dn_sm
1 root 20 0 172504 12332 7892 S 0.0 0.1 0:15.56 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 rcu_gp
4 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 rcu_par_gp
8 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 mm_percpu_wq
9 root 20 0 0 0 0 S 0.0 0.0 0:22.93 ksoftirqd/0
10 root 20 0 0 0 0 I 0.0 0.0 2:49.48 rcu_sched
11 root 20 0 0 0 0 I 0.0 0.0 0:00.00 rcu_bh
12 root rt 0 0 0 0 S 0.0 0.0 0:00.44 migration/0
14 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/0
15 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/1
16 root rt 0 0 0 0 S 0.0 0.0 0:01.10 migration/1
17 root 20 0 0 0 0 S 0.0 0.0 0:16.63 ksoftirqd/1
20 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/2
----------------------------------------------------------------------------------------------------------------
SWITCH--B
top - 22:35:39 up 2 days, 7:10, 1 user, load average: 0.79, 0.74, 0.73
Tasks: 325 total, 1 running, 324 sleeping, 0 stopped, 0 zombie
%Cpu(s): 6.9 us, 4.4 sy, 0.0 ni, 87.9 id, 0.0 wa, 0.0 hi, 0.8 si, 0.0 st
KiB Mem : 16377636 total, 13097076 free, 2479760 used, 800800 buff/cache
KiB Swap: 1637760 total, 1637760 free, 0 used. 13580832 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1720 root 20 0 4022580 378072 114260 S 16.7 2.3 972:22.34 base_nas
1303 root 20 0 3851080 63880 32332 S 11.1 0.4 201:52.12 dn_sm
3911 admin 20 0 41300 3364 2656 R 11.1 0.0 0:00.03 top
1 root 20 0 140592 8376 5288 S 0.0 0.1 0:36.11 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.01 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:24.25 ksoftirqd/0
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
7 root 20 0 0 0 0 S 0.0 0.0 4:18.51 rcu_sched
8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh
9 root 20 0 0 0 0 S 0.0 0.0 1:09.61 rcuos/0
10 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcuob/0
11 root rt 0 0 0 0 S 0.0 0.0 0:00.83 migration/0
12 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 lru-add-drain
13 root rt 0 0 0 0 S 0.0 0.0 0:00.51 watchdog/0
14 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/0
15 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/1
16 root rt 0 0 0 0 S 0.0 0.0 0:00.30 watchdog/1
In addition this model of switch S5248F-ON was not mentioned as been affected by memory leakage.
DELL-Joey C
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May 13th, 2024 04:07
Hi,
Based on the both outputs, it look normal. The report of memory full might be false. I may suggest check if both switches are at their latest firmware. If no, do update them to the latest.
haryortheyji
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May 14th, 2024 13:44
Thanks I believe you right. I was able to make identify the monitoring server provide false information about the memory.