Originally Posted by Puwaha
As your data grows, you expose yourself to greater risk with FlexRAID. With ZFS' self-healing filesystem and data integrity... it protects against silent data corruption/bit-rot... and does this on the fly, and in a scheduled "scrub." Granted FlexRAID offers something similar with it's "Verify" function, but this effectively renders your server unusable for hours or even days depending on how much data you have. You have to run a whole verify job too, or it's worthless... so during those painful hours or days, don't change any data on your server, because there is no way to run an update. Don't try to watch a movie, or hope that your DVR-HTPCs hard drives don't fill up, because you won't be able to move DVR recordings.
What's the big deal about bit-rot? There are numerous examples, but a real life study of 1.5 million HDDs in the NetApp database found that on average 1 in 90 SATA drives will have silent corruption... which is not caught by hardware RAID verification processes (much less software.) For a RAID-5 system that works out to one undetected error for every 67 TB of data read. On a full 3TB HDD you can easily hit that 67TB in no time.
I know where you are going with this argument. And the ability to pull a hard drive and have access to the raw NTFS files is a good safety-net. But think about this... how many times have you ever done this with a WHSv1, SnapRAID or FlexRAID hard drive? In fact the only time you would ever do this is in a catastrophic server failure, or you are decommissioning a server. You don't just yank hard drives out of your server unless they are bad.
This doesn't happen very often, to almost render this plus for FlexRAID pretty moot. As long as you haven't lost more than your fault-tolerance disks, you can import a ZFS set of disks into another server with near instant access... with one simple command. And you can do this hardware-agnostically, just as with a single NTFS/FlexRAID disk.
Agreed. I did state that my needs had outgrown FlexRAID. ZFS is an enterprise class product versus a one-man show (no matter how talented that one man may be)... so who do you trust your data to? It's not just movies we are talking about here. It's music, photos, backups, documents, and much more... and more importantly your precious and expensive time.
Here are some other pros for ZFS as compared to FlexRAID:
1. No need for hardware RAID cards. ZFS was designed with cheap commodity hard drives in mind, not expensive RAID-capable or enterprise disks. Granted FlexRAID fits into this category as well... except when it comes to bit-rot which is more prevalent in commodity consumer-level hard drives.
2. No need for "checkdisk" or "fsck" type apps to correct filesystem problems... Besides, those apps take your data offline to check, meaning you can't stream movies while chkdsk runs on a 3TB hard drive!
3. Pooled storage without the need to re-run first-time parity when you add more hard drives. Calculating that first parity can take a long time in FlexRAID. Every time you add a new HDD to FlexRAID, you must run the first parity sync all over again, and with every new disk the process gets longer and longer. ZFS adds disks instantly.
4. ZFS pools stay online if you are rebuilding a RAID-Z set. With FlexRAID, your pool is offline while you rebuild.
5. Instantly create your pool/filesystem - No need to wait hours while the first parity build takes place, it's on the fly with ZFS.
6. True RAID-Z ability... mix and match RAID levels in the same pool... mix and match RAID-0, RAID-1, RAID-5, etc.
7. Snapshots/Rollback - Make a snapshot, and you now have a "Time-Machine"-like set of data saved with no extra effort or disk space. Only changes to the snapshot are written to disk. You can run snapshots daily, hourly, or every minute if you are ultra-paranoid and have a lot of changing data. Snapshot-RAID cannot compete here.
8. Copy-on-Write - pull the power plug on your in the middle of a file write and nothing bad happens with ZFS Try that with your NTFS backed FlexRAID system.
9. ZFS is space efficient - built in compression (modern CPUs are more than able to keep up)... you can compress files on the fly to free up more hard disk space.
10. Huge filesystems... up to 16 exabytes Why would you ever need that much? Who could imagine a 4TB drive 10 years ago?
11. Deduplication... great for backups or sets that have a lot of the same data.
12. Simple backups: "zfs send" command
13. On the fly Encryption
14. It's free! No need to purchase an OS license or RAID license.
It's worth noting that even Brahim recognizes that FlexRAID isn't perfect for every user and is trying to implement ZFS-like features in his "NZFS" product.