Introduction and purchase suggestions for ApsaraDB RDS for SQL Server storage types - ApsaraDB RDS

Introduction to storage types

Note

For more information about the performance comparison of different storage types, such as maximum capacity per disk, maximum IOPS, and maximum throughput, see Block storage performance.
Disks (ESSDs) meet the reliability, durability, and read/write performance requirements in the product SLA. They use a distributed architecture with multiple replicas. If your RDS instance runs RDS High-availability Edition or RDS Cluster Edition, automatic switchover completes in seconds.

ESSDs

Enhanced SSD (ESSD) is a new ultra-high performance cloud disk product from Alibaba Cloud. Based on a new-generation distributed block storage architecture, ESSDs use 25GE networks and Remote Direct Memory Access (RDMA) technology. They provide up to 1 million random read/write input/output operations per second (IOPS) for a single disk and lower one-way latency than standard SSDs. ESSDs are available in the following categories:

PL1 ESSD: An ESSD at performance level (PL) 1.
PL2 ESSD: Compared to PL1, a PL2 ESSD increases IOPS and throughput by about two times.
PL3 ESSD: Compared to PL1, a PL3 ESSD increases IOPS by up to 20 times and throughput by up to 11 times. It is suitable for business scenarios that require extremely high concurrent I/O performance and stable read/write latency.

For more information about the performance of ESSDs, see ESSDs.

View the storage type

You can view the storage type of an instance on the Basic Information page.

Performance data of storage types

Comparison item	ESSD
I/O performance	★★★★★ IOPS: determined by the disk specifications and instance type. I/O latency: 100 to 200 microseconds
Configuration flexibility	★★★★★ Multiple configuration options with storage capacity scale-out.
Backup method	Snapshot backup for ESSDs
Speed of backup, read-only instance creation, and instance cloning	★★★★★ Completes in seconds.
Scale-out duration	★★★★★ Online upgrade. Scale-out completes in seconds.
Impact of scale-out	No impact.
Data durability	★★★★★ 99.9999999% data reliability. Supports single-node Basic Edition instances to reduce costs.

References

For more information, see FAQs about buckets.