### Instruction:
Based on the paragraph below, what are some key elements to consider in designing an OLTP system?

### Input:
Systems design
To build an OLTP system, a designer must know that the large number of concurrent users does not interfere with the system's performance. To increase the performance of an OLTP system, a designer must avoid excessive use of indexes and clusters.

The following elements are crucial for the performance of OLTP systems:

Rollback segments
Rollback segments are the portions of database that record the actions of transactions in the event that a transaction is rolled back. Rollback segments provide read consistency, rollback transactions, and recovery of the database.
Clusters
A cluster is a schema that contains one or more tables that have one or more columns in common. Clustering tables in a database improves the performance of join operations.
Discrete transactions
A discrete transaction defers all change to the data until the transaction is committed. It can improve the performance of short, non-distributed transactions.
Block size
The data block size should be a multiple of the operating system's block size within the maximum limit to avoid unnecessary I/O.
Buffer cache size
SQL statements should be tuned to use the database buffer cache to avoid unnecessary resource consumption.
Dynamic allocation of space to tables and rollback segments
Transaction processing monitors and the multi-threaded server
A transaction processing monitor is used for coordination of services. It is like an operating system and does the coordination at a high level of granularity and can span multiple computing devices.
Partition (database)
Partition use increases performance for sites that have regular transactions while still maintaining availability and security.
Database tuning
With database tuning, an OLTP system can maximize its performance as efficiently and rapidly as possible.

### Response:
The designer of an OLTP system must ensure that the number of concurrent users does not interfere with the performance of the system. Some key elements include rollback segments (which record actions of transactions to enable rollback if needed); clusters (data schema which which improves performance of join operations); discrete transactions (ensures the data is not changed until the transaction is committed, which improves performance); block size (reduces unnecessary I/O by ensuring data block size is a multiple of operating system block size); buffer cache size (when SQL statements are tuned to use buffer cache, it avoids unnecessary consumption); dynamic allocation of space to tables and rollback segments; transaction processing monitors (used for coordination of services, acting as kind of an operating system that can span multiple computing devices); database partitions (using partitions increases performance while balancing availability and security); and database tuning (allowing the OLTP system to maximize its performance efficiently and rapidly).