Determining the amount of memory Adaptive Server can use

Table 3-2 lists the upper limits of addressable shared memory for Adaptive Server versions 12.0 and later:

**Table 3-2: Addressable memory limits by platform**
Platform	32-bit Adaptive Server	64-bit Adaptive Server
HP-UX 11.x (PA-RISC processor)	2.75 gigabytes	16 EB¹
IBM AIX 5.x	2.75 gigabytes	16 EB
Sun Solaris 8 (sparc processor)	3.78 gigabytes	16 EB
Sun Solaris 8 (Intel x86 processor)	3.75 gigabytes	N/A
Red Hat Enterprise Linux (Intel x86 processor)	2.7 gigabytes	N/A

¹One exabyte (EB) equals 2⁶⁰, or 1024 petabyte. 16 exabyte is a theoretical limit; in practice, the actual value is limited by the total memory available on the system. Adaptive Server has been tested with a maximum of 256GB of shared memory.

²Starting Windows with the /3G option allows Adaptive Server to use up to 3 gigabytes of shared memory. See your Windows documentation.

Adaptive Server 12.5 and later allocates memory differently than earlier versions. This includes changes to existing memory-related configuration parameters and introduces new memory parameters.

Each operating system has a default maximum shared-memory segment. Make sure the operating system is configured to allow the allocation of a shared-memory segment at least as large as max memory. See the Installation Guide for your platform.