ApsaraDB RDS for PostgreSQL storage types and recommendations - ApsaraDB RDS

Storage types

Note

For a performance comparison between storage types, including capacity per disk, maximum IOPS, and maximum throughput, see Block storage performance.
The reliability, durability, and read/write performance of cloud disks, including ESSDs and Premium ESSDs, meet the service level agreement (SLA). These storage types are based on a distributed cloud disk architecture and use multi-replica redundancy to ensure data reliability. If your RDS instance is a High-availability Edition or Cluster Edition instance, it supports automatic failover within seconds.

ESSDs

Enhanced SSDs (ESSDs) are a new generation of ultra-high-performance cloud disks from Alibaba Cloud. Built on a next-generation distributed block storage architecture with 25GE networking and Remote Direct Memory Access (RDMA) technology, ESSDs provide up to 1 million random IOPS and lower one-way latency than a standard SSD. ESSDs are available in the following performance levels (PLs):

ESSD PL1: An ESSD at performance level 1 (PL1).
ESSD PL2: Compared with PL1, an ESSD at PL2 delivers approximately double the IOPS and throughput.
ESSD PL3: Compared with PL1, an ESSD at PL3 delivers up to 20 times the IOPS and 11 times the throughput. This level is ideal for workloads that require extremely high concurrent I/O performance and highly stable read/write latency.

Premium ESSDs

A Premium ESSD is compatible with all features of an ESSD and provides advanced features, including I/O performance burst, Buffer Pool Extension (BPE), and data archiving. For more information, see Premium ESSD.

View the storage type

You can view the storage type on the instance's Basic Information page.

The Storage Type field displays the instance's current storage type, such as ESSD PL1. To upgrade the storage type, click the adjacent Upgrade Storage Type link.

Performance comparison

Item	ESSD	Premium ESSD
I/O performance	★★★★★ IOPS: Determined by the disk specifications and instance specifications. I/O latency: 100–200 microseconds	★★★★★★ In addition to the features of ESSDs, Premium ESSDs provide I/O performance burst and Buffer Pool Extension (BPE). IOPS: Determined by the disk specifications and instance specifications. I/O latency: 100–200 microseconds
Configuration flexibility	★★★★★ Offers multiple configuration options. Supports scaling storage capacity up or down. Note Scaling down storage is supported only for ApsaraDB RDS for PostgreSQL instances that meet specific conditions. For more information, see Change instance specifications.	★★★★★ Offers multiple configuration options. Supports scaling storage capacity up or down. Note Scaling down storage is supported only for ApsaraDB RDS for PostgreSQL instances that meet specific conditions. For more information, see Change instance specifications.
Backup method	ESSD snapshot backup	ESSD snapshot backup
Speed of backup, read-only instance creation, and instance cloning	★★★★★ Completes in seconds.	★★★★★ Completes in seconds.
Scaling duration	★★★★★ Online expansion that completes in seconds.	★★★★★ Online expansion that completes in seconds.
Impact of scaling	None.	None.
Data durability	★★★★★ It provides 99.9999999% data durability and supports single-node Basic Edition instances to reduce costs.	★★★★★ It provides 99.9999999% data durability and supports single-node Basic Edition instances to reduce costs.

Recommendations

Prioritize Premium ESSDs. Consider them for the following scenarios:

If your workload is I/O-intensive, consider enabling Buffer Pool Extension (BPE).
If your workload experiences significant I/O fluctuations, consider enabling I/O performance burst.
If your database contains many tables that are infrequently accessed or modified, consider enabling data archiving.

If you require a specific performance level (PL), choose an ESSD.

ApsaraDB RDS:Storage types