The purpose of this blog is to explain what a Virtual Tape Library (VTL) is and how IBM i (AS400/iSeries) users can benefit from this technology.
What Is A VTL?
A Virtual Tape Library, or VTL, is a disk-based technology that emulates a tape library for backup and restore.
The disk technology is similar to a disk-array SAN. Physically, it looks like a 5U rack-based expansion chassis full of disk units. Physical dimensions can vary.
The VTL often use SAS or SATA disk units as the primary storage component due to their relatively low cost. For lightning performance some will use Solid State Drives (SSDs).
It can connect to an IBM POWER server with various attach features, including SAS, Fiber, and SCSI.
Because the VTL emulates an IBM 3850 Tape Library, it can be installed and use your exiting backup software and commands.
VTL Is Generally Faster Than Tape Backup
By backing up data to disks instead of tapes, VTL often increases performance of both backup and recovery operations. My clients that use them notice VTL backups are dramatically faster than tape.
Practically speaking, restores are also much faster because you don’t have to hunt down a tape, mount it, and then scan the tape for the desired file. Like any disk solution, the file you want to recover is instantly accessible from the VTL.
Generally speaking, you conduct a full Save21 system save. Thereafter, you perform daily incremental backups. You many also conduct Month-End or other periodic saves for retention. As I said earlier, access to historical online data is easy and fast.
Data Deduplication Shrinks Your Physical Backups
Some VTLs offer data deduplication. Data deduplication scans files after the backup is completed to deduplicate redundant data. This can shrink the physical size of the backup by 10:1 or more.
Save Your VTL Backup To Archive Tape Or Off-Site Online Backup To The Cloud
VTL data can be saved to archive tape or replicated to another VTL for off-site storage to the cloud. You also have the option to encrypt your data when you move it off the VTL.
5 VTL Benefits
While a VTL may cost about 30% more than an IBM 3580 Tape Library ($12,500 vs $9,500), I think the VTL offers a lot of value.
1) You can reduce the number of tapes you need to rotate your backup. That n be a $400-
$1000 per year annual media savings.
2) The VTL is RAID protected whereas a tape drive is a single-point of failure.
3) You dramatically reduce cost of managing tapes and related offsite storage. Rather than weekly loading, removing, labeling and handling of tape, you may reduce offsite tape backup to once per month. My clients estimate the labor savings to be about $3,000 – $5,000 per year.
4) A VTL can dramatically shrink your backup window as well as improve the reliability of your backup. You also have the added benefit of instant restore of retained backup data. While my clients love this capability, no one has been told me how much money it saves.
5) A VTL can provide the foundation for offsite backup and recovery from a hosted cloud server. With an offsite hosted cloud server, you can recover from your backup in a matter of hours instead of days.
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