2008-03-14 12:40 AM
Today, we don't use VTL. But we do a lot disk to disk backup (snapvault). So, in our mind, we are completly shifted to backup on disk and we were looking to a VTL to replace our last tape robot.
But in the context of power and cooling (and the cost of this) in the data center, the tape library has an hugh advantage: they don't consume power (when you compare this with D2D our VTL).
Has someone some thoughts about this? Power is for me the biggest disadvantage for VTL.
2008-03-14 05:25 AM
VTLs were not viable until ATA storage came along because cost does matter. ATA disk was the enabling technology for VTL. Because of Sarbanes-Oxley, there will probably always be a requirement for tape because it is offline and offsite, but data deduplication will challange the economics of tape beyond the enablement of ATA disks.
2008-03-14 01:26 PM
I think it's really usefull for Incremental and differential backups. Where you are going to use to expire the images in a short period of time and restores are faster.
Full backups for 7 year retentions i think still the Tape is best. In some cases we can write a FULL backup on to VTL in fast and quick later during off peak hours we can transfer the data to tape. In this scenorio we have the advantage of full backup online for 30 days for faster writes and restores
2008-03-19 02:39 AM
I would agree with the other posts. I don't think VTL can replace tape when it comes to long term retention of data. Not just the power, but also the floor space. Tape is good if you want to take it offsite and let it sit on a shelf for a few years.
Granted with SnapVault (or even VTL) disk based "backups" are a reality today. But disk based "archive" is not. There are some customers that do not have an archive need. In those cases where they maybe keep backups around for 2-6 weeks (or even 2-4 months), then disk is a viable alternative to tape for a number of reasons (reliability, restore speed, scaling, etc).
In general we are seeing most customer environments keeping tape as part of the backup process. Usually there's already an investment in tape technology and the need to be able to retrieve older archived data. VTL can help with the scaling and longevity of tape libaries, so if that's a concern or goal then it may still be a good item to add to your infrastructure. The main driver for most VTLs is primary backup, but given that your primary backup is already met with Snapvault then your current library will keep functioning as is.