Dell EMC Networking OS10 Switches May Have High Memory Utilization due to Stunnel Process Which Can Result in Unexpected Behavior
Summary: High Memory Utilization of stunnel process which can result in unexpected behavior
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This article is not tied to any specific product.
Not all product versions are identified in this article.
Symptoms
Affected release 10.5.0.x.
Dell EMC OS10 switches running 10.5.0.x use the stunnel process in VLT sync communication.
In some rare cases, it may be seen that stunnel memory builds up after a period of uptime. This is a result of stunnel not releasing memory as expected. This is seen in the below output that the stunnel process is using 28.4% of the memory at 2G~.
OS10# show process node-id 1 | grep stunnel
651 root 20 0 4286236 2.292g 4616 S 0.0 28.4 170:12.25 stunnel4
This results in low memory and other processes not being able to run due to a lack of free memory when this builds up. This can result in unstable behavior when the switch free memory becomes low. This can include but is not limited to; reloads, vlt sync failure, SNMP failure, so on.
To confirm that current free memory will be checking the available memory divided by total memory.
OS10# show processes node-id 1 | grep Mem
KiB Mem: 8151628 total, 4115292 free, 3238844 used, 797492 buff/cache
KiB Swap: 815160 total, 815160 free, 0 used. 4616136 avail Mem
The expected free memory percentage depends on each switch, deployment, and environment as such an expected value is not the same for every use case. Should this free memory become low due to stunnel process schedule a reload and upgrade of the switch operating system.
NOTE: There have not been any reports of this on Isilon solutions.
Dell EMC OS10 switches running 10.5.0.x use the stunnel process in VLT sync communication.
In some rare cases, it may be seen that stunnel memory builds up after a period of uptime. This is a result of stunnel not releasing memory as expected. This is seen in the below output that the stunnel process is using 28.4% of the memory at 2G~.
OS10# show process node-id 1 | grep stunnel
651 root 20 0 4286236 2.292g 4616 S 0.0 28.4 170:12.25 stunnel4
This results in low memory and other processes not being able to run due to a lack of free memory when this builds up. This can result in unstable behavior when the switch free memory becomes low. This can include but is not limited to; reloads, vlt sync failure, SNMP failure, so on.
To confirm that current free memory will be checking the available memory divided by total memory.
OS10# show processes node-id 1 | grep Mem
KiB Mem: 8151628 total, 4115292 free, 3238844 used, 797492 buff/cache
KiB Swap: 815160 total, 815160 free, 0 used. 4616136 avail Mem
The expected free memory percentage depends on each switch, deployment, and environment as such an expected value is not the same for every use case. Should this free memory become low due to stunnel process schedule a reload and upgrade of the switch operating system.
NOTE: There have not been any reports of this on Isilon solutions.
Cause
10.5.0.x use stunnel process for VLT communication between peers. This version of stunnel susceptible to possible memory concerns.
Resolution
In later releases starting with 10.5.1.0, the stunnel process architecture for the VLT sync process is no longer used. These releases are not susceptible to this memory concern.
The recommended action is to upgrade to 10.5.2.x or a newer release.
The recommended action is to upgrade to 10.5.2.x or a newer release.
Affected Products
PowerSwitch S3048-ON, PowerSwitch S4048-ON, Dell EMC Networking MX5108n, Dell EMC Networking MX9116n, Dell EMC Networking N3200-ON, PowerSwitch S4048T-ON, PowerSwitch S4112F-ON/S4112T-ON, PowerSwitch S4128F-ON/S4128T-ON
, PowerSwitch S4148F-ON/S4148T-ON/S4148FE-ON, PowerSwitch S4148U-ON, PowerSwitch S4248FB-ON /S4248FBL-ON, PowerSwitch S5212F-ON, PowerSwitch S5224F-ON, PowerSwitch S5232F-ON, PowerSwitch S5248F-ON, PowerSwitch S5296F-ON, PowerSwitch Z9100-ON, PowerSwitch Z9264F-ON, PowerSwitch Z9332F-ON, PowerSwitch Z9432F-ON, SmartFabric OS10 Software
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Article Properties
Article Number: 000193971
Article Type: Solution
Last Modified: 05 Jun 2025
Version: 4
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