EMC ECS VDC Disk Capacity Test

Virtual Data Centre (VDC) is a geographical location defined as a single ECS deployment within a site in a single or multiple racks. VDC is defined using the IP address of the nodes in the system. VDC forms a physical boundary for data and can be used to separate the data and users for different clients. Each VDC will have several disks belonging to different pools and nodes.

The purpose of this test is to look at the storage profile of the VDC at any given time like how much capacity is used and how much is available for various requirements. The insights gained from this test help administrators to plan the capacity for supporting the existing clients’ needs and upcoming business requirements, and of any issue or potential issue which needs addressing.

Target of the test : A Dell EMC Elastic Cloud Storage System

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each Virtual Data Centre (VDC)

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed .


The host for which the test is to be configured. Since the storage device is managed using the IP address of its storage controller, the same will be displayed as host.


The port number at which the specified host listens. By default, this is NULL.


This is the port at which REST API connectivity is provided. By default, port 4443 is used.

Username and Password

To collect performance metrics from the target storage device, the eG agent should be configured with the credentials of a user who is vested with "read-only" privileges to access REST API of the target storage device. Specify the credentials of such a user in the Username and Password text boxes.

Confirm Password

Confirm the password by retyping it here.

Timeout Seconds

Specify the time duration for which this test should wait for a response from the storage system in the Timeout text box. By default, this is 60 seconds.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Number of disks

Indicates the total number of disks in a VDC.


The health of VDC is evident from the availability of the disks, if a large number of disks are offline or under maintenance, the VDC's capacity to store data will be reduced.




Good disks

Indicates the number of disks in VDC which are online.


Bad disks

Indicates the number of disks in VDC which are offline.


Maintenance disks

Indicates the number of disks in VDC which are under maintenance.


Total space

Indicates the total capacity of the VDC that is currently online. This is the total of the capacity already used and the capacity still free for allocation.


Capacity of VDC is dependent on the availability of disk space, measures related to size of disk capacity indicate ability of VDC to accommodate more incoming data. If the amount of space available in a VDC is less, you may have to think about capacity planing.




Indicates the disk capacity which is already allocated in the VDC.



Indicates the online disk capacity which is available to be allocated in the VDC.



Online capacity available for use, including approximately 10% of the total capacity that is reserved for failure handling and for performing erasure encoding or XOR operations.


EMC Elastic Cloud Storage takes a number of necessary steps to ensure data is protected against failure. The processes like failure handling, geo copy, geo cache, data protection ensure that user data is quickly available and protected against disk, node or site failure. The measures related to size gives a indication of how much space is available for user out of total disk space available.







Offline disk space total

Total disk space which is allocated and is offline at the time of measurement.


Geo copy

Indicates the disk capacity used to cache chunks that are accessed locally but not stored locally in the VDC.


Geo cache

Indicates the capacity used for Geo-replication chunks stored on the current VDC.


System metadata

Indicates the capacity used by ECS processes that track and describe the data in the system. This capacity is not available to users for storage.


User data

Indicates the capacity used by repository chunks representing data uploaded by ECS users.


Protection overhead

Indicates the amount of capacity occupied by encoding which provides enhanced protection for data.