Use this task to improve the performance of long-running business
processes, by balancing the hardware resources.
Why and when to perform this task
Before you start to tune the system, verify that the computer used
is well balanced, so that the available CPU, memory, and disk space resources
have the right relationship. A computer with fast CPUs, but low memory or
low disk-access performance, is hard to tune.
Steps for this task
- Allocate enough disks.
For long-running processes,
good disk performance and multiple, fast disk drives are as important as a
fast processor and a sufficient amount of memory.
Separate disks provide
independence of operation and are not affected by other operations. A striped
RAID array distributes disk operations over several disks. This can provide
improved performance over an equal number of single disks. Use a striped RAID
array to overcome bottlenecks on single disks.
For
a system that runs long-running processes and does not use a RAID array, set
up six or more disk drives, as follows:
- One disk for the operating system and the swap space (page file on Windows®,
paging space on AIX®,
swap space on Solaris, paging space on HP-UX).
- One disk for WebSphere® Application Server and its transaction
log.
- One disk for the transaction log of the message queuing system.
- One disk for the persistent queue storage of the message queuing system.
- One disk for the transaction log of the database management system.
- One or more disks for the Business Process Choreographer database in the
database management system. If more disks are available, distribute the INSTANCE
tablespace on two or more disks.
- Allocate enough memory.
The amount of memory to allocate
depends on the platform:
- For a Windows system with 3 GB of physical memory, a local
database, and a local WebSphere MQ queue manager, use the following memory
allocation:
- 256 MB for Windows systems
- 1024 MB for WebSphere Application
Server
- 256 MB for WebSphere MQ,
if WebSphere MQ
is used
- 1.5 GB for the database
- For an AIX system
with 8 GB of physical memory, a local database, and local WebSphere MQ
queue manager, use the following memory allocation:
- 512 MB for AIX systems
- 1024 MB for WebSphere Application
Server
- 512 MB for WebSphere MQ
- 5 GB for the database
Tip: To help ensure optimum performance,
do not allocate all memory to the database, because the files you use and
file caching, for example, also consume memory. Avoid situations in which
data must be swapped to disk because insufficient high-speed memory is available.
- For the application server, when running Business Process Choreographer,
allocate more than the default amount of memory. Tuning the heap size of the
application server is described in Tuning the application server.
- Move workload to other machines.
Consider which applications
or subsystems can be moved to other machines.
Result
Your computer hardware is now well balanced.