Availability

The Situation So, you work for a small retail company that pulls in about $15 million in annual sales.  You’re the person in charge of the 10 servers running at HQ, which manages the 15 stores around the tri-state area.  The stores are open 8am to 8pm weekdays, 9am until 7pm on Saturday and closed on Sunday.  That means you have 70 hours of system up-time that is critical to your stores, but you also run a 24-hour on-line marketplace that contributes to the overall revenue. Like most businesses, you have deployed some level of recovery plans for individual applications, entire servers and the complete datacenter.  You probably know your hourly downtime costs that includes indirect costs, like additional labor to get back online, lost data and reputation. Your recovery plan includes human, server, provider or even mother nature ‘error events’, and it includes a defined Recovery Time Objective (RTO) and Recovery Point Objectiv

 Since 1987, I've used almost every available technology to transfer data across disparate infrastructures, including punch cards, platters, tape, floppy devices, portable block storage cartridges and USB devices. Each required some form of data encapsulation into a payload or packet to be sent to a destination, where it was received and presented to the I/O subsystem for processing. The challenge was always understanding the payload's contents, format, and destination. Different ways to replicate dataThe transmission of the data can be broken into three simple categories.  File Level, Byte Level or Block Level replication.  The simplest explanation of the differences is:File Level - Copies all its information at the application level using standard functions of the Operating System. Byte Level - Copies all changed information at the byte level through File System I/O defined t