Remote Backup Replication Continues to Gain Momentum

Data protection from disasters is a necessity. The challenge is getting that protection without breaking the bank and while achieving restore times that can be measured in hours, not days. However, the rapid rise in acceptance of electronic remote replication for backups, as shown in a recent survey, indicates that the challenge is being met.

Data protection can occur locally and remotely. Backups allow for both physical and logical data protection. The first location of a backup is traditionally at a local site. However, having a second copy of the backup at a remote (that is, at a far enough distance to avoid a regional disaster) disaster recovery (DR) site is a good idea. Manually moving tape copies off site is a tried-and-true method, but the length of time before applications can be restored (which may be days) is increasingly unacceptable in an always-on world. Many backups are now done to disk rather than tape using a disk-based backup approach such as virtual tape library (VTL).

Another alternative is to use electronic remote replication as opposed to manually transporting tapes. The problem with using a network to back up over a distance has historically been not only the bandwidth cost but also the time that takes to do the backup (in addition to the cost of the array on which the backup is stored). Companies can reduce the amount of data that has to be transmitted each day (and hence the time it takes) through the use of data deduplication in conjunction with a VTL. That would indicate--in theory, anyway--that electronic remote replication can be cost effective. (Note that, for this discussion, replication does not imply mirroring, which allows applications to be restarted from a remote array. In this discussion, replicated data still has to be restored before it can be used.)

Survey Sheds Light on Remote Replication

Sepaton--which provides data protection and VTL products--conducted a survey to examine the remote replication and disaster recovery priorities for large enterprise backup environments. This is the fourth annual survey that Sepaton has commissioned for North America and Europe across a number of verticals. The size of the backups was notable: more than half (55%) have full backup volumes of more than 50 Tbytes, and 14% have full backups of more than one petabyte.

Next: Active and Passive ApproachesAccording to the survey results, electronic remote replication seems to be making good progress and is a growing trend. In response to the question "What is your current recovery (DR) strategy?" 21% of the respondents responded with active-active, meaning two or more fully configured data centers with full data sets maintained in all. While this was only a fifth of the total number of respondents, it was greater than the 18% who use physical tapes stored off-site as their primary DR strategy.

Active/active is a relatively more-expensive strategy than other approaches, and many companies cannot afford this degree of protection. Forty-one percent of the respondents use an active-passive disk solution, where there is one fully configured data center with only critical data backed up to a remote site. Together, active-active and active-passive mean that more than three-fifths of all respondents use electronic remote replication at least to some extent, which indicates a substantial adoption.

The next question that arises is how much of the data is currently replicated to a DR site over a network? Almost half--47%--of the respondents say that they back up more than half (51% or more) of their data, with 12% going so far as to say that they back up 91% to 100% of their data. That confirms a strong trend toward electronic remote replication.

Note that remote offices also need DR protection for their data. The 2012 survey showed that 15% of the data in those sites is not backed up or protected. That seems shocking, but it is a significant improvement over the greater than one third of the data that the 2011 survey revealed.

A key question in Sepaton's survey was: "What are your main IT priorities for data protection 2012/2013?" It should come as no shock that 46% have rated "increasing backup performance" as critical. One of the ways to improve performance is to add remote replication for DR, and about 60% viewed it as a moderate to critical priority, which is consistent with the adoption rate of electronic remote replication.

Note that although the first line of backup is becoming disk-based, tape is not dead. Sepaton reports that keeping tape on site for a tertiary copy of data is still a viable option. In this case, a VTL becomes a disk-based cache. The use of tape can help companies balance costs and provide physically distinct backup media.

Sepaton is a client of David Hill and Mesabi Group.