High Availability
Overview
24x7 operations and web-based services are demanding continuous access to critical data and the direct and indirect costs of an unplanned outage are rising fast.
It remains a fact that the more aggressive the Recovery Point Objectives (RPOs) and Recovery Time Objectives (RTOs), the greater the cost. Consequently high availability solutions were limited to the larger data centres. However, in recent years the range of high availability solutions has expanded and reached a price-point where they are affordable for most mid-market organisations.
The key architectural considerations around building Highly Available data and storage management solutions are:
Redundancy in the storage network and storage devices
A fundamental design principal for any centralised storage solution is to avoid single points of failure. Enterprise disk, Mid-Range disk and switches will have varying degrees of redundancy in key components and non-disruptive failover features. The extent of redundancy within the various storage and fabric devices varies, as you would expect, with cost.
Advanced backup and copy services
Snapshot tools provide a fast disk-based copy of mission-critical systems and enable copies of the data to be taken at far more regular intervals than traditional backup. A RPO may be as low as minutes.
Replication
Mirroring differs from
Advanced Backup and Copy Services firstly because the source and target usually reside on different subsystems at some distance. Secondly, mirroring reflects all the changes that are made on the source to the target and not a copy at some point-in-time
Continuous Data Protection
For organisations who require fast recovery and aggressive RPO in their Windows environment, for example Exchange or SQL databases, including individual emails or calendar entries, CPD can deliver dramatic improvements.
Storage Service Management
Despite increasing automation in the storage environment, the ability of an organisation to avoid unplanned outages rests with the storage administrators and managers. Modern storage devices and software produce a large quantity of information and alerts concerning performance. A growing challenge is to monitor this information and use it for key management tasks such as capacity planning. Storage Service Management software provides a 'dashboard' over the whole environment enabling managers and administrators to manage more data and storage.
Vendor Alliances
