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  6. Disk-intensive ECSs

Disk-intensive ECSs

Overview

D1 ECSs are developed based on XEN virtualization. They are designed for applications requiring sequential read/write on ultra-large datasets in local storage (such as distributed Hadoop computing) as well as large-scale parallel data processing and log processing.

Compared with D1 ECSs, D2 ECSs are developed based on KVM virtualization. They use local storage and provide high storage performance and intranet bandwidth for distributed Hadoop computing, large data warehouse, distributed file system, data processing, and log processing.

Specifications

Table 1 D1 ECS specifications

ECS Type

vCPUs

Memory (GB)

Flavor

Virtualization Type

Local Disks (GB)

Hardware

D1

4

32

d1.xlarge

XEN

3 x 1800

  • V3 series

    CPU: Intel® Xeon® Processor E5-2690 v3

    Memory: 12 x 32 GB

  • V4 series

    CPU: Intel® Xeon® Processor E5-2690 v4

    Memory: 16 x 32 GB

8

64

d1.2xlarge

XEN

6 x 1800

16

128

d1.4xlarge

XEN

12 x 1800

36

256

d1.8xlarge

XEN

24 x 1800

Table 2 D2 ECS specifications

ECS Type

vCPUs

Memory (GB)

Flavor

Virtualization Type

Local Disks (GB)

Hardware

D2

4

32

d2.xlarge.8

KVM

2 x 1800

CPU: Intel® Xeon® Gold 6151 Processor v5

Memory: 20 x 32 GB

8

64

d2.2xlarge.8

KVM

4 x 1800

16

128

d2.4xlarge.8

KVM

8 x 1800

24

192

d2.6xlarge.8

KVM

12 x 1800

32

256

d2.8xlarge.8

KVM

16 x 1800

60

540

d2.15xlarge.9

KVM

24 x 1800

Scenarios

  • Applications

    Disk-intensive ECSs are suitable for applications that require large volumes of data to process, high I/O performance, and rapid data switching and processing.

  • Application scenarios

    Big data computing, network file systems, data processing, MapReduce, Hadoop, and data-intensive computing

Features of D1 ECSs

D1 ECSs have the following features:

  • HDD-based data storage
  • Enhanced SR-IOV network performance. On D1 ECSs, SR-IOV is enabled by default, providing high PPS performance and low network jitter and latency.
  • Up to 24 local disks, 36 vCPUs, and 256 GB memory capacity

Features of D2 ECSs

  • D2 ECSs use local disks to provide high sequential read/write performance and low latency, improving file read/write performance.
  • D2 ECSs provide powerful and stable computing capabilities, ensuring efficient data processing.
  • D2 ECSs with a vCPU/memory ratio of 1:8 process large volumes of data.
  • D2 ECSs provide high intranet performance, including high intranet bandwidth and packet per second (pps), meeting requirements for data exchange between ECSs during peak hours.
  • Each D2 ECS supports a maximum configuration of 24 local disks, 60 vCPUs, and 540 GB memory.

Notes on Using D1 ECSs

  • D1 ECSs do not support NIC hot swapping.
  • D1 ECSs do not support modifying specifications.
  • D1 ECSs do not support OS reinstallation or change.
  • D1 ECSs do not support automatic recovery.
  • D1 ECSs support the following OSs:
    • Windows Server 2016 DataCenter 64bit
    • Windows Server 2012 Standard 64bit
    • Windows Server 2012 DataCenter 64bit
    • Windows Server 2012 R2 DataCenter 64bit
    • Windows Server 2012 R2 Standard 64bit
    • Windows Server 2012 R2 Essentials 64bit
    • Windows Server 2008 R2 DataCenter 64bit
    • Windows Server 2008 R2 Enterprise 64bit
    • Windows Server 2008 WEB R2 64bit
    • Windows Server 2008 R2 Standard 64bit
    • Windows Server 2008 R2 SP1 Enterprise 64bit
    • CentOS 7.3 64bit
    • CentOS 7.2 64bit
    • CentOS 7.1 64bit
    • CentOS 7.0 64bit
    • CentOS 6.8 64bit
    • CentOS 6.7 64bit
    • CentOS 6.6 64bit
    • CentOS 6.5 64bit
    • CentOS 6.4 64bit
    • CentOS 6.3 64bit
    • Debian 8.0 64bit
    • Debian 8.4 64bit
    • Debian 8.5 64bit
    • Debian 8.6 64bit
    • OpenSUSE 42.2 64bit
    • Ubuntu Server 16.10 64bit
    • Ubuntu Server 16.04 64bit
    • SUSE Linux Enterprise Server 11 SP3 64bit
    • SUSE Linux Enterprise Server 11 SP4 64bit
    • SUSE Linux Enterprise Server 12 64bit
    • SUSE Linux Enterprise Server 12 SP1 64bit
    • SUSE Linux Enterprise Server 12 SP2 64bit
    • RedHat Linux Enterprise 6.8 64bit
    • RedHat Linux Enterprise 7.0 64bit
    • RedHat Linux Enterprise 7.2 64bit
    • RedHat Linux Enterprise 7.3 64bit
    • Fedora 25 64bit
    • Oracle Enterprise Linux 6.8 64bit
    • Oracle Enterprise Linux 7.3 64bit
    • CoreOS 1185.5.0 64bit
    • EulerOS 2.2 64bit
  • The primary and extension NICs of a D1 ECS have specified application scenarios. For details, see Table 3.
    Table 3 Application scenarios of the NICs of a D1 ECS

    NIC Type

    Application Scenario

    Remarks

    Primary NIC

    Applies to vertical layer 3 communication.

    N/A

    Extension NIC

    Applies to horizontal layer 2 communication.

    To improve network performance, you can set the MTU of the extension NIC to 8888.

  • D1 ECSs can use both local disks and EVS disks to store data. Use restrictions on the two types of storage media are as follows:
    • Only an EVS disk, not a local disk, can be used as the system disk of a D1 ECS.
    • Both an EVS disk and a local disk can be used as the data disk of a D1 ECS.
    • A maximum of 60 disks (including the system disk and local disks) can be attached to a D1 ECS. For details about restrictions, see section Can Multiple Disks Be Attached to an ECS?
      NOTE:

      The maximum number of disks attached to an existing D1 ECS remains unchanged. To attach 60 disks, enable advanced disk. For details, see section Enabling Advanced Disk.

Notes on Using D2 ECSs

  • D2 ECSs support the following OSs:
    • CentOS 6.7/6.8/7.2/7.3/7.4 64bit
    • SUSE Enterprise Linux Server 11 SP3/SP4 64bit
    • SUSE Enterprise Linux Server 12 SP1/SP2 64bit
    • Red Hat Enterprise Linux 6.8/7.3 64bit
    • Windows Server 2008 R2 Enterprise 64bit
    • Windows Server 2012 R2 Standard 64bit
    • Windows Server 2016 Standard 64bit
    • Debian 8.7/9/9.0.0 64bit
    • EulerOS 2.2 64bit
    • Fedora 25/26 64bit
    • OpenSUSE 42.2/42.3 64bit
  • When the physical host where a D2 ECS is deployed becomes faulty, the ECS cannot be migrated.
  • To improve network performance, you can set the NIC MTU to 8888.
  • D2 ECSs do not support modifying specifications.
  • D2 ECSs do not support local disk snapshot or backup.
  • D2 ECSs do not support OS reinstallation or change.
  • D2 ECSs do not support automatic recovery.
  • D2 ECSs can use both local disks and EVS disks to store data. In addition, they can have EVS disks attached to provide a larger storage size. Use restrictions on the two types of storage media are as follows:
    • Only an EVS disk, not a local disk, can be used as the system disk of a D2 ECS.
    • Both an EVS disk and a local disk can be used as the data disk of a D2 ECS.
    • A maximum of 60 disks (including VBD, SCSI, and local disks) can be attached to a D2 ECS. Among the 60 disks, the maximum number of SCSI disks is 30, and the VBD disks (including the system disk) is 24. For details, see section Can Multiple Disks Be Attached to an ECS?
      NOTE:

      The maximum number of disks attached to an existing D2 ECS remains unchanged. To attach 60 disks, enable advanced disk. For details, see section Enabling Advanced Disk.

    • You are advised to use World Wide Names (WWNs), but not drive letters in applications to perform operations on local disks to prevent drive letter drift (low probability) on Linux. Take local disk attachment as an example:

      If the local disk WWN is wwn-0x50014ee2b14249f6, run the mount /dev/disk/by-id/wwn-0x50014ee2b14249f6 command.

      NOTE:

      How can I view the local disk WWN?

      1. Log in to the ECS.
      2. Run the following command to view the WWN:

        ll /dev/disk/by-id

  • The local disk data of a D2 ECS may be lost due to some reasons, such as host machine breakdown or local disk damage. If the data reliability of your application cannot be ensured, you are strongly advised to use EVS disks to build your ECS.
  • When a D2 ECS is deleted, its local disk data is automatically deleted. Back up the data before deleting such an ECS. Deleting local disk data is time-consuming. Therefore, a D2 ECS requires a longer period of time than other ECSs for releasing resources.
  • Do not store long-term service data in local disks. Instead, back up data in a timely manner and use a high availability data architecture. Store long-term service data in EVS disks.
  • You are not allowed to buy additional local disks. The quantity and capacity of your local disks are determined according to your ECS flavor. For a D2 ECSs, if additional local disks are required, buy them when creating the ECSs.