Home > Storage > ObjectScale and ECS > Product Documentation > Dell ECS: High Availability Design > Introduction
High availability can be described in two main areas: system availability and data durability. A system is available when it can respond to a client request. Data durability is provided independent of system availability and provides guarantees for data being stored in the system without loss or corruption. Thus, even if the ECS system is down (for example, a network outage occurs), the data is still protected.
The distributed nature of the ECS architecture provides system availability by allowing any node in a virtual data center (VDC)/site to respond to client requests. If a node goes down, the client can be redirected either manually or automatically (for example, using DNS or a load balancer) to another node that can service the request.
ECS uses a combination of triple mirroring and erasure coding to write data in a distributed fashion to be resilient against disk and node failures. ECS supports replication between sites to increase the availability and resiliency by protecting against site-wide failures. ECS also includes regular systematic data integrity checks with self-healing capability.
When looking at high availability, you should first understand the architecture and how data is distributed for optimal availability and performance within ECS.