"Sami" == Sami Kapanen sami.kapanen@hamk.fi writes:
Sami> I will check these,
Sami> Rubrik states it is using SnapDiff. Cohesity says it is based on Sami> NAS snapshots as well.
Be careful and look at the details of how those snapshots are used. When doing NDMP backups, yes, the backup is based on a snapshot of the volume. And if you have lots of files, then the restores will be *painful* if you only need one or two files in a 10 million file volume. NDMP isn't really quick on that type of restore in my experience.
Sami> Restore times are important, but not crucial to us (University), Sami> we don't loose millions per day if/when restoring.
So if you keep your students and faculty and staff completely segregated in terms of the volumes they keep their data and home dirs on, then you can provide different levels of backup guarantees. Faculty/Staff get better ones of course.
So if you use snapshots as a way to let users recover files from *oops* moments where they deleted a file an hour ago or so and want it back, then you might run into the issue of someone duming a large new files, or deleting alot of data which all goes into the snapshots, and you run out of disk space... then you have a tough call to make.
Do you delete snapshots to make room? Do you grow the volume?
Same with backups to a degree, if you have a full backup that has been running for a day or two, and you run out of space, do you kill the backup?
The worse case scenario is the tough one. It's been 20+ years since I worked in a Uni, and disk space was always a problem even then, since some users would try to game the system.
John