DB Instance Storage Types

The database system is generally an important part of an IT system and has high requirements on storage I/O performance. You can select a storage type based on service demands. You cannot change the storage type after the DB instance is created.

Description

RDS supports Cloud SSD (also called Ultra-high I/O) and Extreme SSD to suit different performance requirements of your workloads.

Cloud SSD (also called Ultra-high I/O)
Stores data in cloud disks for decoupled storage and compute. The maximum throughput is 350 MB/s.
- For RDS for MariaDB, RDS for PostgreSQL and RDS for MySQL instances, this storage type is displayed as Cloud SSD.
- For RDS for SQL Server instances, this storage type is displayed as Ultra-high I/O.
Extreme SSD
Uses 25GE network and RDMA technologies to provide you with up to 1,000 MB/s throughput per disk and sub-millisecond latency.
- Only RDS for MySQL and RDS for PostgreSQL support extreme SSDs.

Performance Comparison

**Table 1** Performance comparison
Item	Cloud SSD	Extreme SSD
I/O performance	Sub-par I/O performance due to additional network I/O overheads	Higher I/O performance than cloud SSDs
Elastic scalability	Scaling in seconds	Scaling in seconds
Maximum IOPS	50,000	128,000
Maximum throughput	350 MB/s	1,000 MB/s
Read/write latency	1 ms	Sub-millisecond