Business continuity and disaster recovery strategies became even more of a critical concern for most companies after September 11, 2001. And now, with most of the Northeast and some of the Midwest resuming its first week back to work after the biggest power failure in American history, companies are once again talking about the importance of and need for disaster-recovery plans — not just for bouncing back from outages caused by massive natural or man-made disasters, but also from day-to-day events such as software corruption and human errors.
As with most IT strategies, today’s backup and recovery environments are changing. And although tape backup systems continue to play a vital role in backup and recovery, some people are wondering if backup and recovery as we know it today will be obsolete in the next 24 months.
“Tape systems are usually locked away in a vault — protecting them from both manmade and natural disasters,” says Jon Toor, director of marketing at ONStor. However, he continues, being ‘locked away’ also means being hard to access quickly. “In the future, both types of backup – disk and tape – will coexist, and new technologies will make this new pairing both cost effective and simple to manage.”
Zophar Sante, vice president of marketing at SANRAD, believes that tape will continue to lead in the next two years, simply because it takes such a long time to shift a storage architecture, given that most businesses don’t change major IT infrastructure every year — but rather every three years, on average. “Many people who are looking at backup and recovery solutions are looking at disk-based for backup and tape for archiving,” says Sante.
He believes daily backups and SNAPshots are being written to disk for several reasons, including speed, the decrease in disk cost, and iSCSI (storage over IP) support. “By going to online disk systems for backup file repositories, recovery time and simplicity is dramatic – it’s basically instantaneous,” emphasizes Sante.
Does Tape Backup Have a Future?
Disks drives are getting cheaper, and as ATA drives become less expensive, companies may begin to eliminate tape backups altogether and move entirely to disk-based backup. “Low cost disk is a key enabling technology for disk-based back-up”, says Toor.
However, he says, even though IT managers love the concept of fast data restore, the bottom line remains the same — every infrastructure enhancement must pay for itself, and quickly. “SATA arrays will significantly lower the entry cost for enterprise storage, thus making it significantly easier to cost justify disk-to-disk solutions.”
Still, there are some folks who believe that tape will remain the preferred method for archiving data, particularly in data centers where the most mission-critical data is kept. Toor believes the reason for this is that tape provides both security and offsite storage capability. But he also says that disk will play a role because it offers faster, more reliable backups and instant data restore.
“Data center managers have been backing up to tape for years — again they don’t refresh methods every year — but they will back up to disk and then back up those files to tape off-line,” says Toor. “Once the backup files are located on the backup disk system, companies can take more time to migrate those backup files from disk to tape.”
Hot Database Backups and Data Replication Services Heat Up
Companies are also looking toward ‘hot’ database backups (which work while the database is still running), because they can’t afford to shut down their databases. Sante reports that many ONStor customers regularly SNAPshot file systems that contain active databases as well as other data types.
He says the SNAPshots can then be backed up to disk as a background activity, effectively backing up a live database. “The speed of SNAPshots combined with the non-intrusive nature of block-level data replication delivers a form of ‘hot’ database backup,” says Sante.
Toor asserts that open file backup is already a reality. “I think that most major DB players have open file backup agents and know that ‘hot’ backup is a must,” he says. “SNAPshot is a technique that does this already and we are working on volume SNAPshot.”
More and more companies are also showing a greater interest in data replication services. For companies that require offsite disk-based backup, outsourcing a portion of that process may make a lot of sense, according to Sante. “Just as companies find efficiencies in third-party site hosting, the data replication process may benefit from the economies of third-party site maintenance.”
Sante also states that a complication could be the need for seamless interaction between the onsite and offsite locations. “This interaction would be easiest when two sites share common infrastructure, possibly leading to a co-location model rather than a service provider model.”
A Coexistence in Store for Tape and Disk Backup?
Although disk backup will continue to make inroads into tape’s territory, many industry experts believe that organizations will use it as an adjunct rather than a replacement. And as vendors introduce cheaper disk arrays, many companies will use ‘staging to disk’ where disk storage is used for a few months and then the data is moved to tape for long-term storage.
So, it may be that disk and tape will always be complimentary. Much of the appeal of disk-based backup, according to some industry experts, lies largely in its simplicity. Data can be instantly restored from a secondary disk, rather than invoking a complicated restore-from-tape procedure. “An elaborate staging architecture in which data is transitioned among various levels of storage defeats an element of that simplicity, and may in fact be unnecessary,” says Sante.
Many experts agree that tape will continue to be used because it enables data that is not replicated to disk to be stored offsite. In the end, the bottom line is ensuring that the security of data is completely protected, so expect IT managers to stick with tape until the alternatives are exceptionally well proven.