Maximum number of filesystems on AIX 4.1.5

 ENV:           4.1.5   7015 R20

Problem: What is the maximum number of JFS filesystems on AIX 4.1.5

Action Taken: These limitations are largely based on the system VMM or
Virtual Memory Manager.

The following relate to AIX 3.2, 4.1, and 4.2 and ARE subject to

First, all JFS filesystems use the VMM to treat the filesystem as a
paging device.

The VMM keeps track of all paging devices through a paging device
table or PDT.

The current limitation on the number of paging devices in this table
is 512.

Of these entries, 16 are used for standard paging spaces.
Consequently, the maximum number of paging spaces that can be used in
current releases of AIX are 16 and the maximum size of each paging
space is 64gig, with a system wide total of 64gig * 16 or 1 Terabyte.

The remaining entries can be used for JFS filesystem mounts. This
often will be about 480 entries.

Action Plan: CWCA

Testcase: none

Support Line: Maximum number of filesystems on AIX 4.1.5 ITEM: CO8612L
Dated: August 1997 Category: N/A
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