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Why Disk Has Forever Replaced Tape as a Primary Backup Target

Right here, right now, it’s time to state what may sound preposterous to some and obvious to others. Disk has officially forever replaced tape as the primary target for backup software. But the reasons for this go much deeper than disk just now being cheaper, faster and easier to manage than tape. Disk is just one part of a whole new equation that has emerged where near real time business continuity and disaster recovery are the new desired end results.

Many small and midsize enterprises (SMEs) that still use tape as their primary backup target are probably aware that disk has made inroads in replacing tape. But to state that tape’s role as a primary backup target is forever over may sound premature.

Consider these four major technology advancements that have contributed to disk firmly establishing its preeminence over tape from this time going forward.

  • Hard disk drive (HDD) capacities and cost. HDD manufacturers have delivered on forecasted but still hard to believe increases in storage capacities over the last 10 years. In that time, the size of SATA HDDs have increased from about 40 GBs to their present size of 2 TBs, essentially doubling in storage capacity about every 18 months. Further, the price for the physical platter has essentially stayed the same or even dropped over that same period of time such that a 2 TB internal HDD can be obtained for around $100.  Conversely, a 1.5 TB LTO-5 tape cartridge now costs as much or more than disk while offering less raw capacity.
  • Data deduplication. A few years ago, data deduplication was THE breakthrough technology that first enabled disk to begin to replace tape as a primary backup target. Now, data deduplication just makes disk that much more affordable than tape, plus it gives disk-based backup a tape-like property: that of “infinite capacity.”

One of the few remaining arguments for tape is that a tape library will technically never “run out of capacity” because as soon as a tape cartridge fills up it can be replaced with another tape cartridge. However, since up to 97% of the backup data in most businesses is a deduplicate of the data from the previous day’s, week’s and month’s backup, by deduplicating it businesses essentially get this property of tape when they use a disk solution that deduplicates data.

Affordable software versions of data deduplication are now readily available from providers such as Eversync that can achieve deduplication ratios of 10x or greater. For example, using Eversync’s data deduplication in conjunction with fifteen (15) internal 2 TB HDDs, SMEs can achieve effective backup storage capacities of over 300 TBs which, from their perspective and at this stage of the game, meets their definition of “infinite capacity.

  • Replication. Disk’s immobility was another long term road block to the disk’s broader adoption. After all, what good is a backup on disk if your building with all of your data in it is destroyed? But this hurdle too has been overcome in the last few years in large part because of data deduplication.

By deduplicating backup data before it is replicated, the only data that needs to be replicated offsite is the net new data. So once the initial full copy of all of a company’s backup data is replicated offsite, only changes to that data need to be replicated going forward.

Further, since data deduplication is done before any data is replicated, only one copy of all new data is then transmitted to the secondary site. This minimizes the size/bandwidth of the WAN connection that SMEs need to replicate the data and they may even be able to use an existing WAN connection to perform this task.

  • Improvements in backup software technology and licensing. Even with these prior three factors in place, if backup software could not backup or recover from disk, manage backup data once it is on disk, or only did so at a price that was cost-prohibitive to most SMEs, it would still be premature to declare that disk had replaced tape as a primary backup target.

This is not the case as backup software from providers such as Eversync illustrates. It backs up and recovers from disk.  It can manage the replication of backup data between two sites. All of its backup, data deduplication, recovery and replication features (along with many others) are included as part of its capacity based licensing model that SMEs find predictable and easy to understand.

Yet these four technical reasons as to why disk has replaced tape as a primary backup target fail to account for many of the intangible reasons that are also driving disk’s adoption. What do not appear on any ROI spreadsheet are the dramatic improvements in personal quality of life and peace of mind that every individual who has adopted disk as a backup target shares with me.
Disk eliminates the daily grind and uncertainty that typically surrounds backup to tape. In its stead is a new found sense of relief that backups and restores are completing successfully, completing more quickly and that the worries that administrators have about backup jobs failing coming to an end.

On a broader organizational front, SMEs that use disk as their primary backup target have similar stories to report. Their IT staff is no longer bogged down for hours each day troubleshooting problems associated with failed backup jobs.
Tape administration also comes to an end or is greatly minimized. IT staff no longer needs to swap tapes, move tapes on and off site, store tapes and track what tapes are where. This typically results in SMEs reducing the tens of hours they spend on backup management to just a few hours per week. In so doing, this frees corporate IT staff to refocus on more strategic initiatives that take advantage of this backup data now being on disk.

A formula that summarizes this new environment can be stated as follows:

Disk + Deduplication + Replication + Backup Software =

Near-real Time DR & BC

This is the new equation that is replacing data protection in 2011 and beyond. The software, hardware, technology, money and staff that were once used to deliver “just” data protection can now be repurposed and refocused to deliver on these more strategic business initiatives of disaster recovery and business continuity.
The reasons as to why disk is replacing tape as a backup target go much deeper than disk just now being cheaper, faster and easier to manage than tape. Over the last decade, an entire cast of supporting technologies has also emerged that make it feasible for disk to replace tape as disk-based solutions now offer the benefits that only tape once offered such as infinite capacity, portability and manageability.

But the real reasons as to why disk will replace tape as a primary backup target may have nothing to do with either the financial or the technical reasons. Rather, they may have everything to do with the intangible human reasons as the SMEs and the administrators who work for them want:

  • Less risk and pain in their environment
  • Guarantees that what they have works
  • The time to focus on initiatives that add more value to the business

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