Backups have two distinct purposes. The primary purpose is
to recover data after its loss, be it by data deletion or corruption. Data loss
can be a common experience of computer users. The secondary purpose of backups
is to recover data from an earlier time.
I'm a fan of putting backups and recovery on disk. I'm even a bigger fan of backing up in such a
way that a "recovery" can simply be done by using the backup as the
primary while the real primary is being repaired. It offers the least amount of downtime in
some sort of disaster.
But this does beg the question of whether or not leaving the
backup in the same format as the original leaves it vulnerable in some way that
putting it into a backup format doesn't.
Specifically, I'd say that a copy is no more of less susceptible than a
file on disk that's in some kind of "backup" format. Either one could be deleted by a malicious
admin, unless you were storing it on some kind of WORM file system. The same is true of backups stored on
tape. If someone has control of your
backup system, it doesn't take a rocket scientist to quickly relabel all your
tapes, rendering them completely useless to your backup system.
What makes something a backup (versus just a copy) is not
its format? The question is whether or
not it has management, reporting, and cataloging built around it so that it is
useful when it needs to be in that sense, a CDP or near-CDP style backup is
actually more of a backup than a tar tape, assuming the tar tape is just the
result of a quick tar command. The tar
tape has no management, reporting, or cataloging, other than what you get on the
Backup products that are making instant recovery a reality
are my favorite kind of products. These include
CDP and near-CDP style products like Simpana, Zerto, Veeam, AppAssure,
RecoverPoint, and any of the storage array or storage virtualization products
that accomplish backup via snapshots and replication. This is the way backup
should be done.
Backup continuously or semi-continuously, and recover
instantly by being able to use the backup as the primary when bad stuff