Double-Take应用场景.PPT

* * * * Double-Take provides continuous data protection to ensure minimal data loss and easy and immediate recovery from any disaster or system outage. It utilizes patented real-time replication technology that captures byte-level changes as they happen and replicates those changes to one or more target servers at any location, locally or at a recovery site miles away. Today, Renasant Bank is a Windows? 2000 and 2003 shop with 150+ servers in two locations, the headquarters in Tupelo and an off-site technology center in West Tupelo. Traffic is replicated 24x7 across a 15MB smart-ring connection from the technology center to the headquarters, which acts as their disaster recovery site. * * * The first key metric is Recovery Point Objective (RPO). RPO defines how much data will be lost in the recovery procedure. If a single disk drive in a RAID 5 array fails, you would lose no data - this is an RPO of zero. If the entire disk array fails and you have to restore from tape, you will lose all the data added to the database since the last backup. This is an RPO of 12-24 hours. This also assumes that your full and all incremental backups are usable. The second critical metric is Recovery Time Objective (RTO). RTO measures how long the entire recovery process takes before users can reconnect to their applications and continue working. If a virus corrupts a database, and you simply need to restore it from tape, you may be able to accomplish this in an hour or two, depending on how large the database files are and how fast the all of the associated backup media can be located and restored. This is an RTO measured in hours or days, during which users will be unable to use the application. If an entire production server fails and must be rebuilt, the RTO may be greater than 24 hours, depending on how long it takes to repair or locate new hardware, reinstall the operating system and applications, retrieve the tapes, and restore the data. Once you have quantif