Re: I smell something funny
Seriously, what are you talking about? You obviously have no clue about ZFS and what is does. I suggest you read more on ZFS before writing weird things. Or are you just trying to spread FUD?
"...ZFS appliances give you less than a 100TB usable due to everything having to be RAID 1 and a lack of hardware RAID protection making them use a lot of empty space for sparing (plus a slightly higher amount of ZFS overhead)..."
What less than 100TB? There are PetaByte ZFS servers out there. Wrong.
And what do you mean with "everything having to be RAID 1"? ZFS has no RAID 1. ZFS has raidz1 (corresponds to raid-5) and raidz2 (corresponds to raid-6) and raidz3 (corresponds to none, it allows 3 disks to fail which is unique). Wrong again.
What do you mean with "lack of hardware raid protection"? Dont you know that hardware raid is quite unsafe, and that ZFS provides a superior protection? Dont you know that there are research on this? Dont you know that hardware raid might corrupt your data, without you ever knowing it? Dont you know that ZFS is built to detect data corruption so ZFS is also safer from a data corruption view point? Have you missed the research papers on data corruption? Dont you know that hardware raid is susceptible to "write hole error", but ZFS is built to eliminate that design flaw? Dont you? Wrong again.
"...So basically, you aren't going to get that many backups, so you cannot do things like keep historical backups...."
This is just so wrong it is not even funny. ZFS has snapshots because it is CoW. Each time you make a snapshot, every change is written to a new place on the disk, but all old data is still left intact. This way you can have many snapshots (costing nothing, only the changes are recorded) going back and forth in time. Just like Apple OS X Time Machine. So you can keep historical backups.
Do you work for NetApp or EMC, trying to FUD about ZFS? Or are you just ignorant, claiming weird things without even nothing anything about ZFS?