最近一組3650堆疊交換機出現如下log報警：%PLATFORM-4-ELEMENT_WARNING:Switch 1 R0/0: smand: 1/RP/0: Used Memory value 91% exceeds warning level 90%

交換機型號，版本如下：
Switch Ports Model SW Version SW Image Mode
—— —– —– ———- ———- —-
* 1 52 WS-C3650-48TD 16.3.6 CAT3K_CAA-UNIVERSALK9 INSTALL
2 52 WS-C3650-48TD 16.3.6 CAT3K_CAA-UNIVERSALK9 INSTALL
3 52 WS-C3650-48TD 16.3.6 CAT3K_CAA-UNIVERSALK9 INSTALL

原因分析
經檢查，Switch 1的內存利用率91%，其它兩臺正常。
3650-Switch#show platform software Status control-processor brief
Load Average
Slot Status 1-Min 5-Min 15-Min
1-RP0 Healthy 0.33 0.51 0.56
2-RP0 Healthy 0.36 0.43 0.45
3-RP0 Healthy 0.75 0.44 0.31

Memory (kB)
Slot Status Total Used (Pct) Free (Pct) Committed (Pct)
1-RP0 Warning 3959052 3619608 (91%) 339444 ( 9%) 4255468 (107%)
2-RP0 Healthy 3959052 2213476 (56%) 1745576 (44%) 2850308 (72%)
3-RP0 Healthy 3959052 1055124 (27%) 2903928 (73%) 1253308 (32%)

3650-Switch#show platform software status control-processor
1-RP0: online, statistics updated 2 seconds ago
Load Average: healthy
1-Min: 0.43, status: healthy, under 5.00
5-Min: 0.60, status: healthy, under 5.00
15-Min: 0.68, status: healthy, under 5.00
Memory (kb): warning
Total: 3959052
Used: 3618932 (91%), status: warning
Free: 340120 (9%)
Committed: 4255048 (107%), over 99%
Per-core Statistics
CPU0: CPU Utilization (percentage of time spent)
User: 3.50, System: 1.50, Nice: 0.00, Idle: 94.90
IRQ: 0.00, SIRQ: 0.10, IOwait: 0.00
CPU1: CPU Utilization (percentage of time spent)
User: 4.50, System: 1.00, Nice: 0.00, Idle: 94.50
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00
CPU2: CPU Utilization (percentage of time spent)
User: 3.50, System: 1.10, Nice: 0.00, Idle: 95.39
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00
CPU3: CPU Utilization (percentage of time spent)
User: 4.99, System: 1.99, Nice: 0.00, Idle: 92.90
IRQ: 0.00, SIRQ: 0.09, IOwait: 0.00

2-RP0: unknown, statistics updated 9 seconds ago
Load Average: healthy
1-Min: 0.15, status: healthy, under 5.00
5-Min: 0.39, status: healthy, under 5.00
15-Min: 0.59, status: healthy, under 5.00
Memory (kb): healthy
Total: 3959052
Used: 2212872 (56%), status: healthy
Free: 1746180 (44%)
Committed: 2850140 (72%), under 95%
Per-core Statistics
CPU0: CPU Utilization (percentage of time spent)
User: 4.00, System: 1.30, Nice: 0.00, Idle: 94.70
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00
CPU1: CPU Utilization (percentage of time spent)
User: 2.10, System: 0.70, Nice: 0.00, Idle: 97.20
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00
CPU2: CPU Utilization (percentage of time spent)
User: 5.40, System: 2.60, Nice: 0.00, Idle: 92.00
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00
CPU3: CPU Utilization (percentage of time spent)
User: 3.10, System: 0.90, Nice: 0.00, Idle: 96.00
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00

3-RP0: unknown, statistics updated 6 seconds ago
Load Average: healthy
1-Min: 0.11, status: healthy, under 5.00
5-Min: 0.16, status: healthy, under 5.00
15-Min: 0.21, status: healthy, under 5.00
Memory (kb): healthy
Total: 3959052
Used: 1054684 (27%), status: healthy
Free: 2904368 (73%)
Committed: 1253312 (32%), under 95%
Per-core Statistics
CPU0: CPU Utilization (percentage of time spent)
User: 1.79, System: 0.79, Nice: 0.00, Idle: 97.30
IRQ: 0.00, SIRQ: 0.09, IOwait: 0.00
CPU1: CPU Utilization (percentage of time spent)
User: 2.30, System: 0.90, Nice: 0.00, Idle: 96.80
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00
CPU2: CPU Utilization (percentage of time spent)
User: 1.70, System: 0.30, Nice: 0.00, Idle: 97.99
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00
CPU3: CPU Utilization (percentage of time spent)
User: 3.20, System: 0.70, Nice: 0.00, Idle: 96.10
IRQ: 0.00, SIRQ: 0.00, IOwait: 0.00

查詢了一番，是這個版本的ios bug，網上有不少相同的案例，根據思科官網case記錄，也有類似的問題
https://www.cisco.com/c/en/us/support/docs/field-notices/701/fn70110.html
https://quickview.cloudapps.cisco.com/quickview/bug/CSCvf59313

解決方法
升級交換機ios至官方推薦的穩定版本。