ApsaraDB RDS:What are general ESSDs?

Description

The general ESSD storage type is supported by ApsaraDB RDS for PostgreSQL. General ESSDs support all the features of ESSDs and provide the I/O burst, I/O acceleration, and data archiving features. When I/O loads increase but the storage capacity of an RDS instance remains unchanged, general ESSDs can deliver higher IOPS and queries per second (QPS) than ESSDs.

• I/O burst: If your workloads significantly fluctuate and the peak hours frequently change, you can enable the I/O burst feature of general ESSDs for your RDS instance. This way, the IOPS of the general ESSDs is no longer limited by the maximum IOPS. This improves the I/O performance of the RDS instance to handle workload bursts during peak hours. For more information, see Use the I/O burst feature.

• I/O acceleration: If the disk I/O becomes a performance bottleneck of your RDS instance, you can use the I/O acceleration feature of general ESSDs to significantly improve the I/O performance of the RDS instance when a large number of read and write requests need to be processed. For more information, see Use the I/O acceleration feature.

• Data archiving: In most cases, the data of an RDS instance is divided into hot data and cold data. If your RDS instance contains a large amount of data, you can use the data archiving feature and store the cold data in Object Storage Service (OSS) buckets. For more information, see Use the data archiving feature. If your RDS instance contains a large amount of data, you can use the data archiving feature and store the cold data in OSS buckets. This significantly reduces storage costs.

Performance of general ESSDs

• I/O performance: General ESSDs deliver better baseline I/O performance than performance level 1 (PL1) ESSDs and provide the I/O burst and I/O acceleration features. The increase in baseline I/O performance of general ESSDs varies based on the storage capacity of your RDS instance. The following table describes the differences. For more information, see [Product changes/Feature changes] The baseline I/O performance of the general ESSDs of ApsaraDB RDS instances is increased.

  Storage capacity of a general ESSD	Original baseline I/O performance (same as PL1 ESSD)	Improved baseline I/O performance	Increment
  100 GB ≤ Storage capacity < 1,000 GB	I/O bandwidth: 125 MB/s to 350 MB/s IOPS: 6,800 to 50,000	I/O bandwidth: 225 MB/s to 450 MB/s IOPS: 13,200 to 56,400	I/O bandwidth: 100 MB/s IOPS: 6,400
  1,000 GB ≤ Storage capacity < 2,000 GB	I/O bandwidth: 350 MB/s IOPS: 50,000	I/O bandwidth: 500 MB/s IOPS: 59,600	I/O bandwidth: 150 MB/s IOPS: 9,600
  2,000 GB ≤ Storage capacity < 4,000 GB	I/O bandwidth: 350 MB/s IOPS: 50,000	I/O bandwidth: 550 MB/s IOPS: 62,800	I/O bandwidth: 200 MB/s IOPS: 12,800
  4,000 GB ≤ Storage capacity < 16,000 GB	I/O bandwidth: 350 MB/s IOPS: 50,000	I/O bandwidth: 600 MB/s IOPS: 66,000	I/O bandwidth: 250 MB/s IOPS: 16,000
  16,000 GB ≤ Storage capacity < 64,000 GB	I/O bandwidth: 350 MB/s IOPS: 50,000	I/O bandwidth: 700 MB/s IOPS: 72,400	I/O bandwidth: 350 MB/s IOPS: 22,400

• Configuration flexibility: Various configuration options are provided, and you can increase or decrease the storage capacity of an RDS instance.

  Note

  You can reduce the storage capacity of RDS instances that meet specific requirements. For more information, see Change instance specifications.

• Backup method: Snapshot backup is supported.

• Time required for backup, read-only instance creation, and instance cloning: Only a few seconds are required.

• Time required for storage capacity expansion: Online storage capacity expansion is supported for you to expand the storage capacity of an RDS instance within a few seconds.

• Impact of storage capacity expansion: No impacts are imposed.

• Data durability: General ESSDs support 99.9999999% data reliability and support RDS instances that run RDS Basic Edition to reduce costs.

Limits

• The storage capacity of general ESSDs ranges from 10 GB to 64,000 GB.

• You cannot change the storage type of your RDS instance from general ESSD to a different storage type. However, you can change the storage type from ESSD to general ESSD. For more information, see Change the storage type from ESSD to general ESSD.

Billing rules

General ESSD fee = Fee for the storage capacity that you purchase for your RDS instance + I/O burst fee + I/O acceleration fee + Data archiving fee

The I/O acceleration feature is provided free of charge. The fee for the storage capacity varies based on the amount that you purchase. The fees for the I/O burst and data archiving features vary based on actual usage. For more information, see the following information:

• The fee for the storage capacity that you purchase is the same as the fee for a PL1 ESSD.

• Billing rules of the I/O burst feature

• Billing rules of the data archiving feature

Purchase a general ESSD

You can use one of the following methods to purchase a general ESSD for an RDS instance: