IBM manual Domino R5 on AIX Specifics

Lotus Domino Server R5 Implementation Guide June 18, 2001

Among the key Domino R5 features that enable it to scale with these platforms are:

ŸUnlimited database size (currently certified up to 64 GB), to support increased database workloads.

ŸDirectory scalability in excess of one million users, to easily handle the directory requirements of even the largest deployments. (Lotus has tested a Domino R5 Directory with 10 million entries)

ŸDatabase optimizations to better exploit high-end I/O and CPU throughput.

ŸSupport for online indexing, online database compacting, and online backup; to take advantage of high-end systems and I/O subsystems.

ŸIncreased overall scalability enabling support for more users on fewer partitions, to drive down per-user costs across large, partitioned servers.

Domino R5's ability to keep running during scheduled maintenance tasks like database compaction, indexing and backup makes server consolidation in general more attractive, since large numbers of users will not be inconvenienced due to scheduled outages.

And R5's greater scalability and new high availability features make server partitioning a more attractive alternative than ever. Partitioning yields lower total cost of ownership: administration and maintenance are simplified, and fewer moving parts increases reliability, security and availability (if one partition fails, others remain available).

Domino R5 on AIX Specifics

Domino R5 on AIX leverages many platform-specific services directly. For example, R5's new thread pooling capability was optimized specifically for AIX. And Domino R5's high-availability features are particularly well-integrated and complement those of HACMP of AIX. For example, R5's transaction logging makes performance and UNIX® auto-restart features even more effective, by allowing Domino to restart very quickly.

For customers using Domino as a Web application server on AIX, R5 clustering supports both failover and load balancing for Web clients. And the Domino R5 Server's clustering features are complementary to HACMP on AIX, such as high-speed interconnects, disaster tolerance and support for many-node clusters. In fact, Domino clustering in combination with AIX-based clustering can bring system availability into the 99.99% range.

When looking to size a Domino R5 server on AIX, the basics for memory, disk, and network adapters has not changed from R4. What has changed are the scalability factors that can be applied to determine the number of partitions and the number of users per partition. As a rule of thumb, we see the scalability doubled (meaning Domino can now support up to 4 processors per partition with scalable growth as processors are added) and approximately 1.5 to 2 X the number of users per partition. Example: With R4, if we have a 4-way running two partitions of 600 users each for a total of 1200 active users, then R5 with the same 4-way could support the same 1200 active users on a single partition (hence better administration). Therefore, as a guideline:

ŸR4 - one partition for every two processors

ŸR5 - one partition for every four processors

ŸR4 - one partition for every 600 - 800 active users

ŸR5 - one partition for every 1600 - 2000 active users

If workloads are unknown or heavy, then the lower limits should be planned for and then measurements made once in production.

When clustering is used, customers have reported approximately a 20-25% overhead. If calendaring and scheduling is used, an approximate 25% overhead should be applied.

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