After Migration To Solaris 11.3 the "Page Cache" is not able to handle VxFS DISK I/O in the same way as Solaris 10 (Doc ID 2280418.1)

Last updated on JULY 20, 2023

Applies to:

Symptoms

On : 11.3 version, Performance

ACTUAL BEHAVIOR
---------------
Solaris 11.3 is not using Free memory that is available as "Page Cache".
The "Page Cache" is not going above 12/13% of physical RAM and I/O is going to disk.

EXPECTED BEHAVIOR
-----------------------
That Solaris 11.3 uses available memory as a cache.
Similar setup using Solaris 10 U11 could use up to 30-40% of RAM as page cache.

STEPS
-----------------------
The issue can be reproduced at will with the following steps:
1. Copy several big files (15Gb+) that are on VxFS
2. monitor the memory usage with "echo ::memstat | mdb -k"
3. Copy the same files again and see that the copy access the disk instead of using the cache

Changes

 Moved from Solaris 10 U11 to Solaris 11.3.

Cause

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.