How Photon OS in vRealize Operations 8.x onwards utilizes swap space.
Article ID: 340114
Updated On:
Products
VMware Aria Suite
Issue/Introduction
Linux Kernel version, and settings are different between SUSE (vRealize Operations 7.5 and below) and Photon OS (vRealize Operations 8.x and above). The entire memory/swap management mechanism is handled differently.
Environment
VMware vRealize Operations 8.x
Resolution
In SUSE version swap memory would have not been utilized unless there is a shortage of memory.
In Photon OS (which is based on Linux kernel 4.19.97) however, it is expected that you may see swap space utilization even if there is an available memory.
This Linux Kernel will move memory pages which are hardly ever used into swap space to ensure that even more cacheable space is made available in-memory for more frequently used memory pages. This is done to improve the performance of the system.
Note:
Because of that change you may see “Node is experiencing swapping due to memory pressure” false alerts being triggered on vRealize Operations versions 8.0 and 8.0.1 (since it was based on swap memory utilization).
That alert definition has been removed from the 8.1 version and will be replaced with a new alert tailored for this specific Operating System swap utilization mechanism.
Administrators should continue to monitor and ensure they are within the vRealize Operations sizing guideline limits.
In Photon OS (which is based on Linux kernel 4.19.97) however, it is expected that you may see swap space utilization even if there is an available memory.
This Linux Kernel will move memory pages which are hardly ever used into swap space to ensure that even more cacheable space is made available in-memory for more frequently used memory pages. This is done to improve the performance of the system.
Note:
Because of that change you may see “Node is experiencing swapping due to memory pressure” false alerts being triggered on vRealize Operations versions 8.0 and 8.0.1 (since it was based on swap memory utilization).
That alert definition has been removed from the 8.1 version and will be replaced with a new alert tailored for this specific Operating System swap utilization mechanism.
Administrators should continue to monitor and ensure they are within the vRealize Operations sizing guideline limits.
Additional Information
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