Data replication as a means of data protection has seen continuous and increasing adoption since it first emerged in storage systems in 1993. It has evolved into an indispensable component of disaster recovery (DR), as well as for operational backup for applications that require a shorter recovery point objective (RPO) and recovery time objective (RTO) than what traditional tape backups
- Selection of a data replication method should start with a business impact analysis (BIA) to determine required RTOs and RPOs.
- For applications that can't accept data loss (RTO equals zero), synchronous replication is required. Heed latency in synchronous replication because it will drag down application I/O performance. If there is any risk of latency or unreliable bandwidth, or for replication beyond certain distances (50 km to 300 km), asynchronous replication is the way to go.
- Besides the replication mode, application performance can be impacted by the replication platform. Host-based replication competes with applications for valuable processor, memory and I/O resources.
- Have a clear understanding of the bandwidth requirements, impact on bandwidth cost, and how data replication will impact other applications and users. Clearly understand and take advantage of replication features related to bandwidth, such as compression, bandwidth throttling and configurable bandwidth usage depending on the time of day. Consider wide-area network (WAN) optimization devices to preserve bandwidth.
- Replication products that support heterogeneous environments can substantially reduce cost by supporting less-expensive or legacy arrays. They also limit vendor lock-in.
- The disadvantage of vendor lock-in of array-based replication is offset by the advantage of close integration between replication and the storage platform and easier support, eliminating the risk of finger-pointing in multivendor configurations.
This article originally appeared in Storage magazine.
About this author: Jacob Gsoedl is a frequent contributor to "Storage" magazine.
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This was first published in April 2009