Storage Maintenance Window (Erl, Naserpour)
How can access to data in a cloud storage device be preserved during a maintenance outage?
ProblemHardware maintenance on cloud storage devices can require shutting down the device, resulting in loss of data access and disruption of service.
SolutionAn outage prevention system is created to temporarily move the data without interruption during maintenance and other types of outages.
ApplicationLUN migration is applied to temporarily transfer data to a separate cloud storage device during the maintenance window.
Compound PatternsBurst In, Burst Out to Private Cloud, Burst Out to Public Cloud, Elastic Environment, Infrastructure-as-a-Service (IaaS), Multitenant Environment, Platform-as-a-Service (PaaS), Private Cloud, Public Cloud, Resilient Environment, Software-as-a-Service (SaaS)
Cloud storage devices subject to maintenance and administrative tasks may need to be temporarily shut down, thereby causing an outage to cloud service consumers and IT resources that require access to the devices and the data they host.
Figure 1 - The maintenance task carried out by a cloud resource administrator causes an outage for the cloud storage device. Resultantly, the cloud storage device becomes unavailable to cloud service consumers.
Prior to a cloud storage device undergoing a maintenance outage, its data can be temporarily moved to a duplicate, secondary cloud storage device. Cloud service consumers are automatically and transparently redirected to the secondary cloud storage device and are unaware that the primary cloud storage device has been taken off-line.
Live storage migration is used to convert the data as a whole into an isolated mode and move it to the secondary cloud storage device, as follows:
- The target secondary cloud storage device is identified.
- The data replication process is configured.
- LUNs that require replication are selected.
- The service broker is configured to redirect the cloud consumers’ requests to the secondary storage, should the primary one fail.
Figure 2 - The steps carried during to provide constant data access during a maintenance outage window.
- The cloud storage device is scheduled to undergo a maintenance outage.
- Live storage migration moves the LUNs from the primary storage device to a secondary storage device.
- When the LUN’s data has been migrated, requests for the data are forwarded to the duplicate LUNs on the secondary storage device.
- The primary storage is powered off for maintenance.
- When it is confirmed that the maintenance task on the primary storage device has been completed, the primary storage is brought back online. Live storage migration subsequently restores the LUN data from the secondary storage device to the primary storage device.
- When the LUN migration is completed, all data access requests are forwarded back to the primary storage device.
NIST Reference Architecture Mapping
This pattern relates to the highlighted parts of the NIST reference architecture, as follows: