Performance metrics and specifications of block storage devices - Elastic Compute Service

Various block storage devices have different performance metrics and prices. You can select block storage devices that are suitable for specific workloads and applications based on your storage capacity requirements. This topic describes the performance metrics and specifications of cloud disks, local disks, and elastic ephemeral disks.

Note

For information about the billing of block storage devices, see Block storage devices.

Performance metrics

The key metrics that are used to measure the performance of block storage devices include IOPS, throughput, and latency. The performance of specific block storage devices is related to the device capacity. For example, Enterprise SSDs (ESSDs) at different performance levels (PLs) support different capacity ranges.

IOPS: IOPS measures the number of read/write operations that can be performed on a block storage device per second.

High IOPS is critical for transaction-intensive applications such as database applications.

Note

In database applications, data is frequently inserted, updated, and deleted. High IOPS ensures that the system runs efficiently even when swamped with a large number of random read/write operations, and prevents the performance degradation or increased latency caused by I/O bottlenecks.

Common IOPS metrics

Metric	Description	Data access method
Total IOPS	The total number of I/O operations per second.	Access locations on storage devices in a continuous or non-continuous manner.
Random read IOPS	The average number of random read I/O operations per second.	Access locations on storage devices in a non-continuous manner.
Random write IOPS	The average number of random write I/O operations per second.
Sequential read IOPS	The average number of sequential read I/O operations per second.	Access locations on storage devices in a continuous manner.
Sequential write IOPS	The average number of sequential write I/O operations per second.	Access locations on storage devices in a continuous manner.

Throughput: Throughput measures the amount of data that is transferred per second. Unit: MB/s.
High throughput is critical for applications that require a large number of sequential read/write operations, such as offline computing tasks performed by Hadoop.
Note
Offline computing tasks performed by Hadoop require the analysis and processing of petabyte-scale data. Low throughput may result in prolonged overall processing time, which affects business efficiency and response speed.
Latency: Latency measures the amount of time that is required for a block storage device to process an I/O request. Unit: seconds, milliseconds, or microseconds. High latency may cause performance degradations or errors in applications that require low latency.
For latency-sensitive applications such as database applications, we recommend that you use low-latency disks, such as ESSD AutoPL disks and ESSDs.
Capacity: Capacity is the amount of storage space. Unit: TiB, GiB, MiB, or KiB.
You cannot use capacity as a metric to measure the performance of block storage devices, but the maximum performance of block storage devices varies based on the capacity of the devices. A block storage device that has a larger capacity provides stronger processing capabilities. Block storage devices of the same category have the same I/O performance per unit capacity. However, the performance of a cloud disk linearly increases with the disk capacity up to the single-disk maximum performance of the disk category.

Performance of cloud disks

The following table describes the performance and common usage scenarios of different categories of cloud disks.

Important

Standard SSDs, ultra disks, and basic disks are cloud disks of the previous generation and are unavailable for purchase in specific regions and zones. We recommend that you use ESSDs at performance level 0 (PL0 ESSDs) or ESSD Entry disks instead of ultra disks and basic disks and use ESSD AutoPL disks instead of standard SSDs.

Item	ESSD-series disk							Standard SSD	Ultra disk	Basic disk
Item	Regional ESSD (in public preview)	ESSD AutoPL	PL3	PL2	PL1	PL0	ESSD Entry	Standard SSD	Ultra disk	Basic disk
Single-disk capacity range (GiB)	10~65,536	1~65,536	1,261~65,536	461~65,536	20~65,536	1~65,536	10~32,768	20~32,768	20~32,768	5~2,000
Maximum IOPS	50,000	1,000,000	1,000,000	100,000	50,000	10,000	6,000	25,000^②	5,000	Hundreds
Maximum throughput(MB/s)	350	4,096	4,000	750	350	180	150	300^②	140	30~40
Formula for calculating single-disk IOPS^①	min{1,800 + 50 × Capacity, 50,000}	Baseline performance: max{min{1,800 + 50 × Capacity, 50,000}, 3,000} Provisioned performance: min{Provisioned IOPS, 50,000} Burst performance: min{IOPS supported by the instance type, 1,000,000}	min{1,800 + 50 × Capacity, 1,000,000}	min{1,800 + 50 × Capacity, 100,000}	min{1800 + 50 × Capacity, 50,000}	min{1,800 + 12 × Capacity, 10,000}	min{1,800 + 8 × Capacity, 6,000}	min{1,800 + 30 × Capacity, 25,000}	min{1,800 + 8 × Capacity, 5,000}	None
Formula for calculating single-disk throughput (MB/s)^①	min{120 + 0.5 × Capacity, 350}	Baseline performance: max{min{120 + 0.5 × Capacity, 350}, 125} Provisioned performance: min{16 KB × Provisioned IOPS/1,024, Maximum throughput per disk} Burst performance: min{Throughput supported by the instance type, 4 GB/s}	min{120 + 0.5 × Capacity, 4,000}	min{120 + 0.5 × Capacity, 750}	min{120 + 0.5 × Capacity, 350}	min{100 + 0.25 × Capacity, 180}	min{100 + 0.15 × Capacity, 150}	min{120 + 0.5 × Capacity, 300}	min{100 + 0.15 × Capacity, 140}	None
Data reliability	99.9999999%	99.9999999%	99.9999999%	99.9999999%	99.9999999%	99.9999999%	99.9999999%	99.9999999%	99.9999999%	99.9999999%
Average single-channel random write latency in milliseconds (block size = 4 KB)	Value when an instance accesses a disk in the same zone: < 2 Value when an instance accesses a disk in a different zone: < 4	0.2	0.2	0.2	0.2	0.3~0.5	1~3	0.5~2	1~3	5~10

^① In the following examples, a PL0 ESSD is used to describe how to calculate single-disk performance:
- Single-disk maximum IOPS: The baseline IOPS is 1,800 and increases by 12 per additional GiB to up to 10,000.
- Single-disk maximum throughput: The baseline throughput is 100 MB/s and increases by 0.25 MB/s per additional GiB to up to 180 MB/s.

^② The performance of standard SSDs varies based on the size of data blocks. Standard SSDs that contain smaller data blocks deliver lower throughput and higher IOPS. The following table provides a comparison of data blocks.

Data block size (KiB)	Maximum IOPS	Throughput (MB/s)
4	Approximately 25,000	Approximately 100
16	Approximately 17,200	Approximately 260
32	Approximately 9,600	Approximately 300
64	Approximately 4,800	Approximately 300

Performance of local disks

Local NVMe SSDs

The following table describes the performance metrics of local NVMe SSDs that are used by the d3c instance family.

Metric	Single-disk performance	ecs.d3c.3xlarge	ecs.d3c.7xlarge	ecs.d3c.14xlarge
Maximum read IOPS	100,000	100,000	200,000	400,000
Maximum read throughput	4 GB/s	4 GB/s	8 GB/s	16 GB/s
Maximum write throughput	2 GB/s	2 GB/s	4 GB/s	8 GB/s

The following table describes the performance metrics of the local NVMe SSDs that are used by the i4 instance family.

Metric	ecs.i4.large	ecs.i4.xlarge	ecs.i4.2xlarge	ecs.i4.4xlarge	ecs.i4.8xlarge	ecs.i4.16xlarge	ecs.i4.32xlarge
Maximum read IOPS	112,500	225,000	450,000	900,000	1,800,000	3,600,000	7,200,000
Maximum read throughput	0.75 GB/s	1.5 GB/s	3 GB/s	6 GB/s	12 GB/s	24 GB/s	48 GB/s
Maximum write throughput	0.375 GB/s	0.75 GB/s	1.5 GB/s	3 GB/s	6 GB/s	12 GB/s	24 GB/s

Note

The performance data in the preceding table represents the highest performance levels of local storage for the instance families. The instance families support only Linux images. For optimal performance, we recommend that you use the most recent Linux image versions, such as Alibaba Cloud Linux 3.

The following table describes the performance metrics of the local NVMe SSDs that are used by the i4g and i4r instance families

Metric	ecs.i4g.4xlarge and ecs.i4r.4xlarge	ecs.i4g.8xlarge and ecs.i4r.8xlarge	ecs.i4g.16xlarge and ecs.i4r.16xlarge	ecs.i4g.32xlarge and ecs.i4r.32xlarge
Maximum read IOPS	250,000	500,000	1,000,000	2,000,000
Maximum read throughput	1.5 GB/s	3 GB/s	6 GB/s	12 GB/s
Maximum write throughput	1 GB/s	2 GB/s	4 GB/s	8 GB/s

Note

The performance data in the preceding table represents the highest performance levels of local storage for the instance families. The instance families support only Linux images. We recommend that you use the most recent Linux image versions, such as Alibaba Cloud Linux 3, to obtain optimal performance.

The following table describes the performance metrics of the local NVMe SSDs that are used by the i3 instance family.

Metric	ecs.i3.xlarge	ecs.i3.2xlarge	ecs.i3.4xlarge	ecs.i3.8xlarge	ecs.i3.13xlarge	ecs.i3.26xlarge
Maximum read IOPS	250,000	500,000	1,000,000	2,000,000	3,000,000	6,000,000
Maximum read throughput	1.5 GB/s	3 GB/s	6 GB/s	12 GB/s	18 GB/s	36 GB/s
Maximum write throughput	1 GB/s	2 GB/s	4 GB/s	8 GB/s	12 GB/s	24 GB/s

Note

The performance data in the preceding table represents the highest performance levels of local storage for the instance families. The instance families support only Linux images. We recommend that you use the most recent Linux image versions, such as Alibaba Cloud Linux 3, to obtain optimal performance.

The following table describes the performance metrics of the local NVMe SSDs that are used by the i3g instance family.

Metric	ecs.i3g.2xlarge	ecs.i3g.4xlarge	ecs.i3g.8xlarge	ecs.i3g.13xlarge	ecs.i3g.26xlarge
Maximum read IOPS	125,000	250,000	500,000	750,000	1,500,000
Maximum read throughput	0.75 GB/s	1.5 GB/s	3 GB/s	4.5 GB/s	9 GB/s
Maximum write throughput	0.5 GB/s	1 GB/s	2 GB/s	3 GB/s	6 GB/s

Note

The performance data in the preceding table represents the highest performance levels of local storage for the instance families. The instance families support only Linux images. We recommend that you use the most recent Linux image versions, such as Alibaba Cloud Linux 3, to obtain optimal performance.

The following table describes the performance metrics of the local NVMe SSDs that are used by the i2 and i2g instance families.

Metric	Single-disk performance		Overall instance performance^①
Metric	ecs.i2.xlarge and ecs.i2g.2xlarge	Other i2 and i2g instance types	Overall instance performance^①
Maximum capacity	894 GiB	1,788 GiB	8*1,788 GiB
Maximum read IOPS	150,000	300,000	1,500,000
Maximum read throughput	1 GB/s	2 GB/s	16 GB/s
Maximum write throughput	0.5 GB/s	1 GB/s	8 GB/s
Latency	Several microseconds

^① Overall instance performance data in the preceding table applies only to the ecs.i2.16xlarge instance type and represents the highest performance levels of local storage for the i2 instance family.

The following table describes the performance metrics of the local NVMe SSDs that are used by the i2ne and i2gne instance families.

Metric	ecs.i2ne.xlarge and ecs.i2gne.2xlarge	ecs.i2ne.2xlarge and ecs.i2gne.4xlarge	ecs.i2ne.4xlarge and ecs.i2gne.8xlarge	ecs.i2ne.8xlarge and ecs.i2gne.16xlarge	ecs.i2ne.16xlarge
Maximum capacity	894 GiB	1,788 GiB	2*1,788 GiB	4*1,788 GiB	8*1,788 GiB
Maximum read IOPS	250,000	500,000	1,000,000	2,000,000	4,000,000
Maximum read throughput	1.5 GB/s	3 GB/s	6 GB/s	12 GB/s	24 GB/s
Maximum write throughput	1 GB/s	2 GB/s	4 GB/s	8 GB/s	16 GB/s
Latency	Several microseconds

The following table describes the performance metrics of the local NVMe SSDs that are used by the i1 instance family.

Metric	Single-disk performance	Overall instance performance^②
Maximum capacity	1,456 GiB	2,912 GiB
Maximum IOPS	240,000	480,000
Write IOPS^①	min{165 × Capacity, 240,000}	2 × min{165 × Capacity, 240,000}
Read IOPS^①	min{165 × Capacity, 240,000}	2 × min{165 × Capacity, 240,000}
Maximum read throughput	2 GB/s	4 GB/s
Read throughput^①	min{1.4 × Capacity, 2,000} MB/s	2 × min{1.4 × Capacity, 2,000} MB/s
Maximum write throughput	1.2 GB/s	2.4 GB/s
Write throughput^①	min{0.85 × Capacity, 1,200} MB/s	2 × min{0.85 × Capacity, 1,200} MB/s
Latency	Several microseconds

^① In the following examples, a local NVMe SSD is used to describe how to calculate single-disk performance:

Single-disk write IOPS: Each GiB of capacity produces 165 write IOPS for up to 240,000 IOPS per disk.
Single-disk write throughput: Each GiB of capacity produces a write throughput of 0.85 MB/s for a maximum of 1,200 MB/s.

^② Overall instance performance data in the preceding table applies only to the ecs.i1.14xlarge instance type and represents the highest performance levels of local storage for the i1 instance family.

Local SATA HDDs

The following table describes the performance metrics of local SATA HDDs.

Metric	d1 and d1ne instance families		d2c instance family		d2s instance family		d3s instance family
Metric	Single-disk performance	Overall instance performance	Single-disk performance	Overall instance performance	Single-disk performance	Overall instance performance	Single-disk performance	Overall instance performance
Maximum capacity	5,500 GiB	154,000 GiB	3,700 GiB	44,400 GiB	7,300 GiB	219,000 GiB	11,100 GiB	355,200 GiB
Maximum throughput	190 MB/s	5,320 MB/s	190 MB/s	2,280 MB/s	190 MB/s	5,700 MB/s	260 MB/s	8,320 MB/s
Latency	Several milliseconds

Note

The overall instance performance data in the preceding table applies only to the ecs.d1.14xlarge, ecs.d1ne.14xlarge, ecs.d2c.24xlarge, ecs.d2s.20xlarge, and ecs.d3s.16xlarge instance types and represents the highest performance levels of local storage for the corresponding instance families.

Performance of elastic ephemeral disks

Based on different IOPS and throughput requirements, two categories of elastic ephemeral disks are available: standard and premium. Standard elastic ephemeral disks are suitable for scenarios with large data volumes and high throughput needs, while premium elastic ephemeral disks are suitable for scenarios requiring small capacity but high IOPS. The following table describes the performance of each type:

Metric	Standard elastic ephemeral disks	Premium elasitc ephemeral disks
Single-disk capacity range (GiB)	64 to 8,192	64 to 8,192
Maximum read IOPS per disk	Either 100 times the capacity or 820,000, whichever is smaller	Either 300 times the capacity or 1,000,000, whichever is smaller
Maximum write IOPS per disk	Either 20 times the capacity or 160,000, whichever is smaller	Either 150 times the capacity or 500,000, whichever is smaller
Maximum read throughput per disk (MB/s)	Either 0.8 times the capacity or 4,096, whichever is smaller	Either 1.6 times the capacity or 4,096, whichever is smaller
Maximum write throughput per disk (MB/s)	Either 0.4 times the capacity or 2,048, whichever is smaller	Either the capacity or 2,048, whichever is smaller
Write I/O density①	20	150
Read I/O density①	100	300

①: I/O density = total I/O / disk capacity, unit: IOPS/GiB, indicating the IOPS capability per GiB.

Test the performance of block storage devices

For information about how to test the performance of block storage devices, see the following topics:

Improve the performance of cloud disks

You can view the monitoring information of cloud disks in the Elastic Compute Service (ECS) console, Elastic Block Storage (EBS) console, or CloudMonitor console and determine whether the performance of cloud disks meets your business requirements or whether cloud disks encounter performance bottlenecks. For more information, see View the monitoring data of a cloud disk.

If the performance of a cloud disk does not meet your business requirements, you can use one of the following methods to improve the disk performance:

If the disk belongs to a category that cannot meet your needs for increased IOPS or throughput, you can change the cloud disk to a category that delivers higher performance and responds more quickly. For example, you can change a standard SSD into a PL1 ESSD. This method is suitable for scenarios in which applications have strict requirements on storage performance and experience significant growth in business scale or traffic volume. For more information, see Change the category of a disk.
If the cloud disk is an ESSD AutoPL disk, you can enable the performance provision or performance burst feature for the disk to improve the disk performance. For more information, see Modify the performance configurations of an ESSD AutoPL disk.
If the disk does not meet your needs for increased IOPS and storage capacity, we recommend that you resize the disk by extending the disk capacity. For more information, see Resize cloud disks. When you extend cloud disks of specific categories, such as PL1 ESSDs, the baseline IOPS of the disks increases with the disk capacity. This means the processing capabilities and performance of the disks are improved. This method is suitable for scenarios in which data volume continues to grow and requires larger storage capacity and higher IOPS. For example, the baseline IOPS of a 40-GiB PL1 ESSD is 3,800, which is calculated by using the following formula: min{1,800 + 50 × 40, 50,000}. When you extend the PL1 ESSD to 100 GiB, the baseline IOPS of the PL1 ESSD increases to 6,800.
To increase disk performance and flexibly manage and optimize storage resource allocation, you can use Logical Volume Manager (LVM). LVM can distribute data across multiple logical volumes (LVs) to allow concurrent data reads and writes and improve disk performance. This method is suitable for scenarios that require highly concurrent access, such as multi-threaded applications and databases. For more information, see Create an LV.
To increase the IOPS and throughput of a disk and ensure data redundancy, you can create a RAID array for the disk. For more information, see Create a RAID array for a Linux instance. For example, you can create a RAID array of the RAID 0 level that includes the disk to improve read/write speeds or a RAID array of the RAID 1 or RAID 10 level that includes the disk to improve disk performance and provide data redundancy.