The other option with tape virtualization is to create a virtual tape so really we
start using disk cache we already start storing it in tape format. Virtual Tape
Libraries are not new. They have been doing it in mainframes for years. The
difference is that we are now doing it in open systems. Just about every
company now offers some type of virtual tape format.
Because virtual tape is normally a large sequential read for restore, or a large
sequential write for back up – at that point a lot of people start to use RAID 3
for their structures.
Some vendors use RAID 3 for that functionality, others use RAID 5, RAID 6 –
very few will use 1+0 because you don’t need your data to be 100% mirrored.
So with tape – the consideration is ‘WHEN a failure happens’. We know
system downtime is expensive but disaster recovery can be more than just
backup. We have to look at the system, the site, the personnel and everything