Determining the Amount of Memory SAP ASE Can Use

There are differences between the upper limits of addressable shared memory for SAP ASE versions 12.0 and later versions.

Addressable Memory Limits by Platform
Platform	32-bit SAP ASE	64-bit SAP ASE
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. SAP ASE has been tested with a maximum of 256GB of shared memory.

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

Note: SAP ASE 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.