ApsaraDB for MongoDB supports two storage types: Enterprise SSDs (ESSDs) and local SSDs. This topic describes the features of the two storage types and their differences.
Storage type description
Storage type | Description |
ESSDs | Enterprise SSDs (ESSDs) are developed by Alibaba Cloud based on the next-generation distributed block storage architecture. ESSDs deliver ultra-high storage performance. ESSDs are integrated with 25 Gigabit Ethernet and remote direct memory access (RDMA) technologies. ESSDs can reduce one-way latencies and handle up to 1 million read and write requests at random per second. ESSDs are provided in three performance levels (PLs) as indicated on the ApsaraDB for MongoDB buy page:
Note For more information about the performance differences of the preceding disk types, see ESSDs. The performance comparison items include capacity range, maximum IOPS per disk, and maximum throughput per disk. |
ESSD AutoPL disks | ESSD AutoPL disks are compatible with all features of ESSDs, provide the same baseline performance as PL1 ESSDs, and deliver provisioned performance capabilities. This way, you can decouple the storage capacity of a disk from the performance of the disk to flexibly handle business fluctuations. Note For more information about the features, specifications, billing, scenarios, and configurations of ESSD AutoPL disks, see ESSD AutoPL disks. |
Local SSDs | Local SSDs reside on the same physical host as the database engine that is run by your ApsaraDB for MongoDB instance. You can store data in local SSDs to reduce I/O latencies. |
For more information about the performance differences of the preceding storage types, see Block storage performance. The performance comparison items include maximum capacity per disk, maximum IOPS, and maximum throughput.
Comparison among the performance of the preceding storage types
Item | ESSD | ESSD AutoPL disk | Local SSD |
I/O performance | ★★★★★ Provides low I/O latency and high I/O performance. | ★★★★★ Provides low I/O latency and high I/O performance, and handles burst I/O. | ★★★★★ Provides low I/O latency and high I/O performance. |
Configuration flexibility | ★★★★★ Provides various configuration options and allows you to separately scale up the storage. The storage cannot be scaled down. | ★★★★★ Provides various configuration options and allows you to separately scale up the storage and provisioned performance. The storage cannot be scaled down. | ★★★★ Provides various configuration options and allows you to scale up the disk storage but not scale down the storage. The disk storage that you can select varies based on the instance type. |
Scaling duration | ★★★★★ Allows you to scale the storage within a few minutes. | ★★★★★ Allows you to scale the storage within a few minutes. | ★★★ Requires a few hours to copy data when you scale up the storage. |
Scale-out impact |
|
| Transient disconnections occur during the scale-out process. |
Comparison among the prices of the preceding storage types
The prices listed in the following table are for reference only. The actual price is subject to the bill displayed in the ApsaraDB for MongoDB console.
Storage type | Price |
PL1 ESSDs | USD 0.33 per GB-month |
PL2 ESSDs | USD 0.66 per GB-month |
PL3 ESSDs | USD 1.32 per GB-month |
ESSD AutoPL disks | Fees for ESSD AutoPL disks include storage fees and IOPS fees.
|
Local SSDs | USD 0.33 per GB-month |
The following examples show how to calculate storage fees:
If the storage type of an ApsaraDB for MongoDB instance is PL2 ESSD with the maximum throughput of 370 MB/s and the storage of the instance is 500 GB, the monthly price is USD 330 (500 GB × 0.66 GB per GB-month).
If the storage type of an ApsaraDB for MongoDB instance is ESSD AutoPL disks, the provisioned IOPS of the instance is 10,000 with the maximum throughput of 500 MB/s, and the storage of the instance is 500 GB, the monthly price is USD 171.408 (500 GB × USD 0.33 per GB-month + USD 0.00000089/IOPS/hour × 24 hours × 30 days × 10000).
View the storage type of an ApsaraDB for MongoDB instance
Log on to the ApsaraDB for MongoDB console. On the Basic Information page of an ApsaraDB for MongoDB instance, check Storage Type in the Specification Information section.