Enterprise SCM administrators realize the valuable service they’re providing to development organizations and strive to avoid outages, but exactly how costly is SCM downtime? Put another way, how much is avoiding Git downtime worth to a company that relies on Git for enterprise software development?
A recent study concluded that a data center outage costs an average of $5,600 per minute in general use cases. To get a more concrete number, assume the cost of a single developer is $50-$300/hour depending on location and faced with SCM downtime, a few hundred of them are unable to be productive.
A developer with a private Git repository or a local read-only mirror can still get some work done, but they can’t get the most recent work from other developers if the master Git repository is down, and they can’t commit their own work. The productivity loss factor may not be 100%, but it’s not trivial either. You also need to include the cost of any schedule impact – days matter when deadlines are looming.
That’s why WANdisco provides non-stop data solutions for Git and Subversion. Zero downtime and continuous availability are guarantees, not perks. Enterprise SCM administrators can count on High Availability (HA) and Disaster Recovery (DR) out of the box, with an aggressive Recovery Point Objective (RPO) and Recovery Time Objective (RTO). When compared to Git MultiSite and SVN MultiSite, one-off home-baked solutions simply aren’t battle tested.
With WANdisco MultiSite products for Git and Subversion, every node in the deployment is a replicated peer node, and every node is fully writable. You can choose how these nodes behave by setting up different replication groups, but for the purposes of HA/DR, you might set up a deployment like this:
In this simplified view, users at two sites have a set of local nodes to use. If one node fails, failover to another is automated by a load balancer (the HA case). Note that all the nodes are active and thus also serve to improve overall performance. In a DR scenario, users at one site can simply switch their Git remote to the load balancer at the other site, which routes them to any of the fully writable nodes at the second site.
This setup is quite simple to achieve with Git MultiSite and a stock load balancer like HAProxy, giving you an effective zero downtime solution at very low cost.