Notes and Constraints
This section describes the constraints on using EVS.
Specifications
Resource Type |
Item |
Description |
---|---|---|
Disk performance |
Major disk performance metrics include IOPS, throughput, and latency. |
Different types of EVS disks have different performance. For details, see Disk Types and Performance. |
Security
Item |
Description |
---|---|
Disk encryption |
|
Quotas
You can log in to the console to view default quotas. You can to apply for a larger quota if needed.
Resource Type |
Default Quota |
---|---|
Tags |
10 |
Disks |
Default quotas vary depending on regions. See the quotas shown on the console. |
Disk capacity (GB) |
|
Snapshots |
Operations
Scenario |
Item |
Description |
---|---|---|
Disk creation |
Maximum number of disks that can be created at a time |
100 |
Disk creation |
Disk creation from snapshot |
|
Disk creation |
Disk creation from backup |
|
Disk creation |
Disk creation from image |
|
Disk creation |
Device type |
The device type of a disk cannot be changed after the disk is created. |
Disk creation |
Disk sharing |
The sharing attribute of a disk cannot be changed after the disk is created. |
Disk creation |
Disk encryption |
The encryption attribute of a disk cannot be changed after the disk is created. |
Disk attachment |
Constraints on region and AZ |
The disk and the server must be in the same region and AZ. |
Maximum number of servers that a non-shared disk can be attached to |
1 |
|
Maximum number of servers that a shared disk can be attached to |
16 |
|
Maximum number of disks that can be attached to an ECS |
This number varies depending on the ECS type. For details, see section "Can I Attach Multiple Disks to an ECS?" in the Elastic Cloud Server User Guide. For a BMS, a maximum of 60 EVS disks (1 system disk and 59 data disks) are supported. |
|
Device name |
|
|
Disk capacity expansion |
Capacity expansion |
Disk capacity can be expanded, but cannot be reduced. |
Capacity expansion of non-shared disks |
Some server OSs support the capacity expansion of non-shared, In-use disks. For details, see . |
|
Capacity expansion of shared disks |
A shared disk must be detached from all its servers before expansion. This means that the shared disk status must be Available. |
|
Expansion increment |
1 GiB |
|
Disk detachment |
System disk detachment |
A system disk can only be detached offline, which means that the server must be in the Stopped state. |
Data disk detachment |
A data disk can be detached online or offline, meaning that its server can either be in the Running or Stopped state. |
|
Disk deletion |
Deletion of disks |
|
/ |
|
|
Snapshot data rollback to disks |
/ |
|
/ |
|
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