- Using disk for long-term archives (seven years or more) is just silly.
- Replicating non-dedupable data tends to suck the life out of your WAN.
- Disk uses power, and we all know that spinning disks up and down uses more power than keeping them spinning.
- Tape is an awesome technology for archives.
Tape media is cheap if you don't need a lot of it, it takes no power, is removeable, and if stored properly, it can be used for those long term regulatory requiements for data archives without you having to buy tons of disk. Just ask the folks at the National Archives what media they use to store a ZETABYTE!
Funny how it's usually the vendors who typically don't integrate with tape well or have a vested interest in selling disk are the onces screaming tape is dead. A survey done last year by Enterprise Strategy Group shows only 18% of conpanies today backup only to disk, and 82% still use tape in one from or another but the "spin" is a bit different.
"In its recent 2010 Data Protection Survey of more than 500 IT professionals, ESG found that transitioning from tape- to disk-based backup is one of the major forces in modernizing backup and recovery. According to the results, respondents have made strides to minimize the use of tape in backup and recovery processes since the 2008 survey. Today, 20% of those surveyed "back up directly to tape only" vs. 33% in 2008, 62% cite "back up to disk and tape" compared to the 53% noted in 2008, and 18% now 'back up to disk only' vs. 14% two years ago."
Look, I whole heartedly agree that disk is the best media for backing up data that needs to be available for recovery. That's why VTL with dedupe, encryption, and optimized replication makes so much sense. The fact that VTL integrates so seamlessly with tape means you can automate your data protection storage tiers to include tape! Simply backup to the VTL (disk), dedupe, and replicate to an offsite VTL, and then let the VTL at the other side spit out encrypted tapes for long-term archives. The whole backup process is changing to include snapshots and continuous protection to disk. Deduped and disk-based encrypted electronic vaulting over WAN is a more efficient way to do DR versus shipping tapes, but tape is still an awesome and efficient tool for long-term archives. The process just needs to be fixed so that it's completely automated via services-oriented data management policies.
Data should be stored on disk at least until business policy states it needs to be deleted or archived, usually 60-90 days. However, some data may need to be available up to a year on object-based searchable disk archives, which better be deduplicated to assure it's stored as efficiently as possible. After that, HSM to tape is the more efficient way to go. In order to simplify operations and reduce costs, tapes should be cut where they will stay, which is in an outsourced cloud facility or an owned DR facility.
Tape sucks for recovery, not backup. Those seven-years-to-forever archives should be offloaded to the least expensive storage medium, which in my opinion is still high-density tape.