EMC ECS VDC Garbage Collection Test

Garbage collection is the background process in ECS that runs periodically and reclaims the space which is marked for deletion. The append-only nature of ECS means that any modification or update on data creates a copy of data while the original objects are marked for deletion. Also, when the objects are deleted, they are only marked for deletion and removed from users' view but the space is not reclaimed. This process generates a lot of unused objects marked for deletion, which makes the job of garbage collector even more important.

The purpose of this test is to collect metrics related to garbage collection and provide insight into the health of the garbage collection process if it is running and working efficiently. Looking at the metrics, administrators can start the process if it is stopped, or if metrics suggest that process is not able to reclaim data or facing some issue, it can be investigated before the entire system starts running out of space.

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 .
Host	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.
Port	The port number at which the specified host listens. By default, this is NULL.
ECS REST API Port	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
Is user GC enabled?	Indicates if the garbage collection is enabled for user data.	Boolean
Is system GC enabled?	Indicates if the garbage collection is enabled for system data.	Boolean
Total detected	Indicates the amount of storage capacity detected which is available for reclaim.	GB
Pending reclamation	Indicates the amount of storage capacity identified as reclaimable but not reclaimed yet.	GB
Unreclaimable	Indicates the amount of storage capacity which cannot be reclaimed at the time of measurement. Administrators can investigate further.	GB
User reclaimed	Indicates the amount of user data already reclaimed by the garbage collector.	GB
System reclaimed	Indicates the amount of system data already reclaimed by the garbage collector.	GB
Total reclaimed	Indicates the amount of total data already reclaimed by the garbage collector, including system data and user data.	GB