Compared to hot areas like security or wireless, data backup and restore may have seemed like IT’s forgotten child – until now.
A perfect storm of disappearing back-up windows (thanks to enormous data growth and nonstop business operations), large-scale catastrophes, increased litigation requiring electronic data discovery and federal regulations governing data retention, has catapulted backup and recovery to IT’s head table.
And, reflecting its newfound status, backup and recovery is taking on a more sophisticated, grown-up name: data protection, which encompasses backup, recovery, archiving, retrieval, disaster recovery and business continuity. Backup and recovery is taking on a more sophisticated, grown-up name: data protection, which encompasses backup, recovery, archiving, retrieval, disaster recovery and business continuity.Text
“This is a phenomenal time for storage, and particularly for data protection,” says Arun Taneja, president of Taneja Group. According to IDC, the back-up, archiving and replication software market will grow from US$4.3 billion in 2003 to $6.58 billion by 2008, representing 54 percent of storage software expenditures.
While the term “data protection” covers a lot of ground, it’s the first four areas – backup, recovery, archiving and retrieval – that are currently of highest interest, says Pete Gerr, senior analyst at Enterprise Strategy Group.
Companies now realize they must be able to recover specific pieces of data from financial records, e-mail, instant messaging logs and the like if it’s subpoenaed as evidence in a legal case, Gerr says.
The bottom line is backup, restoration and safe archiving of electronic data can no longer be a “hope it works” proposition.
Tape falls out of favour
“If the one e-mail that may keep the CEO out of court is the last file written to tape, it’s going to take a very long time to find that file,” Gerr says. Long recovery times mean high legal fees and electronic data discovery service provider costs, not to mention the spotlight it shines on poor records-management discipline, which can lead to further regulations.
Another problem with tape is that despite many advances in the technology, these systems just can’t keep up with the volume of data that needs to be stored in ever-shrinking back-up windows. According to a March 2005 survey conducted by Enterprise Strategy Group, roughly half of 163 respondents said their ability to back up and recover data in a timely fashion has been hurt by the limitations of their tape systems. With disk-to-disk devices and virtual tape libraries, backups can run within reasonable time frames, and more data can be kept online, which enables faster recoveries.Text
Start-ups and disk storage heavyweights now are weighing in with tape alternatives, including disk-to-disk backup, virtual tape libraries, content-addressable storage, continuous data-protection devices, new replication and snapshot schemes, data compression techniques and more.
With disk-to-disk devices and virtual tape libraries, backups can run within reasonable time frames, and more data can be kept online, which enables faster recoveries. Denton Central Appraisal District (DCAD), for instance, switched to a StoneFly Networks disk-based backup system and now can back up its 50 servers in the same amount of time it used to take to back up one.
That’s 0.5T to 2T bytes of backup per night, with a routine average of 400G to 600G bytes of changed data written to back-up disk daily, according to Brad Green, director of information services at DCAD, the fastest-growing county in North Texas.
No wonder users have responded to these new back-up technologies with great enthusiasm. Companies spent $1.7 billion on disk-based storage in 2003, according to Strategic Research.
And according to the March Enterprise Strategy Group study, 18 percent of respondents have permanently replaced their tape libraries with disk-based alternatives, and another 58 percent would consider doing so. Of this latter group, 80 percent believe they will replace at least some of their tape libraries over the next 24 months. Tape is still the least expensive means of long-term archival.Text
“Disk storage is being used either as an exclusive method of backup or as an intermediate or staging area before going to tape,” says Bill North, director of research for IDC’s Storage Software service.
While disk backup has traditionally been seen as more expensive than tape, Gerr advises users to consider not just acquisition costs but also operational and administrative costs that tape requires, such as media management and tape swapping. “Tape is much more labor-intensive than disk,” he says. “So while disk is more costly to procure, the total cost of managing it is far less than the total cost of managing a tape environment.”
But it doesn’t disappear completely
When the Texas county’s storage needs grew fourfold in one year, it switched to disk-based backup in the form of a 4.2T-byte, $50,000 StoneFly IP-based storage-area network fronted by Commvault Systems’ QINetix back-up software. DCAD has since added an additional 5T bytes of disk.
But data is still archived on a Dell tape library – at least for now.
Green’s goal is to completely move away from tape. “You’re resting the strength of your entire business on that millimeter-thin little tape,” he says. “That just doesn’t work for me.” His plan is to implement a hot site and synchronize data between the two locations over a VPN using replication software from StoneFly, as well as NSI Software’s Geocluster technology. “If my plan works, we’ll be able to back up to disk offsite,” he says. Disk storage is being used either as an exclusive method of backup or as an intermediate or staging area before going to tape.Bill North>Text
Tape is still the least expensive means of long-term archival, Green notes, adding he’d continue to use it for very long-term archival purposes. “But for me it’s inherently flawed, too subject to failure and too slow,” he says.
North agrees, saying that “trucks and grocery carts are still less expensive than the bandwidth required by replication.” That’s why companies such as Avamar, EMC (with its content-addressable storage system, Centera) and Data Domain are working on data reduction algorithms to compress or otherwise reduce the amount of data that needs to be stored during backups, thus reducing disk costs and minimizing what needs to be sent.
A consumer call center for a large New York bank is looking into software that stores incremental changes rather than blocks of data so that – in the event that it moves to a disk-based archival strategy – it will have less data to send over the wire. Officials at the call center were recently given the directive to move away from all physical transportation of media to protect confidential data – which eventually will rule out tape even for offsite storage.
The call center made some preliminary steps in that direction when it recently solved its tape library-based back-up woes with a RAID-based virtual tape library from Sepaton. Day-to-day backups now go to a Sepaton disk-based system, traveling to the IBM 3494 tape library only when it’s time for archiving and offsite storage.
With the tape-based system, a full backup could take three days, but by backing up data to a Sepaton virtual tape library, the bank not only can continue using its legacy Tivoli Storage Manager (TSM) back-up software, but also a full backup takes just three hours. Further, buyi