The storage system can connect to multiple hosts and can be shared by multiple users, which can result in conflicts among users. For example, if a host issues many I/O requests or reads or writes a large amount of data, the I/O performance of other hosts might be affected. Virtual Partition Manager allows you to create multiple virtual cache memories called cache logical partitions (CLPRs), each allocated to different hosts, to prevent contention for cache memory and improve I/O performance.
A cache logical partition is a pool of the cache and parity groups in the storage system. Partitioning cache into one or more CLPRs allows storage administrators to dedicate individual CLPRs to a different host, preventing I/O contention for cache memory. Partitioning cache dedicates cache resources for exclusive use by specific applications to maintain priority and quality of service for business-critical applications. Storage administrators can secure or restrict access to storage resources to ensure confidentiality for specific applications. By dedicating resources to each partition as needed, a high quality of service can be maintained for all users.
The virtual cache memory created by the cache partitioning function is called a CLPR. If the Virtual Partition Manager license is not installed on the storage system, you can create up to four CLPRs, including the default CLPR0. If the Virtual Partition Manager license is installed, you can create up to 32 CLPRs, including the default CLPR0.
You can allocate the following resources to CLPRs:
- Parity groups
- External volume groups
- Virtual volumes of Dynamic Provisioning
You can perform Virtual Partition Manager operations using CCI or REST API.
Perform cache partitioning for the following purposes:
- To prevent a host from monopolizing cache memory and degrading the performance of other hosts when multiple hosts share a single storage system and perform large volumes of read and write operations
- To divide cache capacity between external volumes and non‑external‑volume resources
- To allocate cache capacity to each external storage system when external volumes from multiple external storage systems are used