Thread: Reall instance memory
01-20-14, 14:13 #1Registered User
- Join Date
- Jan 2010
Unanswered: Reall instance memory
Hi All, I am working with db2 18.104.22.168 and AIX 7.1. I have been assigned to find out how much memory the production box needs to function normal with reasonable performance. I read from IBM document that:
"The default value of instance_memory is AUTOMATIC.The AUTOMATIC setting results in a value being computed at database partition activation. The computed value ranges between 75 percent and 95 percent of the physical RAM on the system - the larger the system, the higher the percentage. For DB2 database products with memory usage restrictions, the computed"
what does it mean " When allocated Not applicable"?
our box has 20 GB memory so will it occupied 16 GB for instance? if database and applications did not need that much, STMM will free the memory to OS ?
STMM and instance_memory and database_memory are AUTOMATIC.
Really appreciate if somebody clarify this concept.
01-20-14, 17:34 #2Registered User
- Join Date
- May 2003
The most important use of memory in DB2 is for bufferpools, so that data and indexes can be accessed from memory and not disk. The amount of memory that is optimal depends on the size of the database and type of application that is using the database. I would suggest that your company hire a consultant to who can examine all these factors at your company and provide you guidance.M. A. Feldman
IBM Certified DBA on DB2 for Linux, UNIX, and Windows
IBM Certified DBA on DB2 for z/OS and OS/390