Relationship between maxperm and maxperm % in AIX

Relationship between maxperm and maxperm % in AIX

In the AIX system, maxperm-related parameters include two (excluding strict_maxperm), maxperm and maxperm %. When using the vmo-a command, you can only find the value of maxperm, however, the value of maxperm % cannot be found. Only the value of maxperm and maxperm % can be found simultaneously using vmo-Fa. The two parameters are correlated.

1. Check the total physical memory size of the system.

# Bootinfo-r

261619712

2. Compare the output values of vmo-a and vmo-Fa commands.

(1) # vmo-a | grep maxperm

Max perm = 57165864

(2) # vmo-F-

Max perm = 57165864

Maxperm % = 90

Strict_maxperm = 0

3. analyze the relationship between maxperm and maxperm % parameter values

261619712 (physical memory size) * 90% (maxperm % value) = 235457740.8 (Kb)

235457740.8 (90% of total physical memory)/4 (4 kb per page) = 58864435.2 (number of pages)

4. Relationship Summary

We can see from the above that the value of the Maxperm parameter is actually the size calculated by the value of the maxperm % parameter in the total physical memory. Of course, the value is directly converted, you also need to divide the size of a single memory page because the value of the maxperm parameter is in the unit of "page"

5. Modify the value of maxperm % to verify whether the value change of maxperm is correct.

(1) modify the value of maxperm % to 10.

# Vmo-p-o maxperm % = 10

(2) Verify the change of the value of maxpermg and maxperm % again

# Vmo-Fa | grep maxperm

Max perm = 6351758

Maxperm % = 10

Strict_maxperm = 0

As shown above, after the value of maxperm % is modified, the value of maxperm is automatically changed and the page size is maxperm %.