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 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 continu¬ity 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.
The Four Advancements Driving Disk’s Adoption
Consider these four major technology advancements that have contributed to disk firmly establishing its preemi¬nence 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 with 3 TB disks now entering the market. 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 less than $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 deduplica¬tion 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 duplicate of the data from the previous day’s, week’s and month’s backup, by deduplicating this data businesses essentially get this “infinite capacity” property of tape when they use a solution that deduplicates data.
Affordable data deduplication is readily available from providers such as Eversync whose disk-based backup solutions achieve deduplication ratios of 4x or greater. For example, using a deduplication solution in conjunction with fifteen (15) internal 2 TB HDDs, SMEs can achieve effective backup storage capacities of over 100 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 needs to be 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. Even with these prior three factors in place, if backup software could not: 1) backup or recover from disk; 2) manage backup data once it is on disk; or, 3) 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 illustrate. 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 which SMEs find easy to understand.

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