Storage Help (NAS+Media Streaming+RAID+Automatic Backup)

Aloise wrote:
I've done some recent research and many people advised me that RAID may not be the best option as it may fail and during data rebuild if the box hangs, data is gone.

If there's a fire, data is gone. If someone steals your NAS, data is gone. If you aren't paying attention and accidentally delete your files, data is gone. If your NAS is mapped as a network share and you click on a CryptoLocker link in an email, data is gone. Etc, etc.

RAID is for data availability (it allows you to have access to your data even while faulty drives are being replaced) and speed. As knowledgeable people say over and over here in the forum (some even have it in their signatures), RAID is not a substitute for a good backup strategy.

That said, it's easy to see that with the size of today's inexpensive drives and the correspondingly enormous size of 6-bay RAID arrays, hard-drive bit error rates that used to seem completely safe -- like "1 non-recoverable read error in 10^14 (100 trillion) bit reads" -- are now uncomfortably close to "100% chance of a non-recoverable read error somewhere on your RAID array". And the advice you've seen certainly has some basis in reality: When one drive in a RAID array fails, a number of factors conspire to make errors on a second drive more likely.

For this situation, the 4-bay and larger ReadyNAS devices support RAID6, which provides two-disk redundancy. With RAID6, your data is safe unless three drives simultaneously fail. The cost is one drive's worth of storage space: With RAID5, a 6x4TB array provides 20TB of storage, but with RAID6 that array will provide "only" 16TB.

Aloise wrote:
So, I'm still thinking of getting a NAS, but now I'm thinking not to use RAID. Is it worth to have a NAS and not using RAID capabilities? ReadyNAS can work like that?

Yes, the ReadyNAS can be configured for "JBOD" ("Just a Bunch Of Disks"). In a JBOD setup, each drive is its own volume; when one fails, the data on it is gone and cannot be retrieved, but the data on all the other drives is unaffected. JBOD could be ok for a backup of your data, but I wouldn't use it for primary storage.

Aloise wrote:
what option would you suggest for BACKUP? Getting another enclosure for BACKUP so the final setup would be... like... 1 NAS for DATA and 1 NAS for BACKUP? In such scenario, is it possible to connect each other and run some kind of backup software like SyncBack Free to schedule automatic and periodic backup jobs?

There are all sorts of options. If you have a second NAS configured identically to the first, you can make it a mirror of your main NAS; if you ever need to take your main NAS out of service, you can replace it with the backup with essentially zero downtime. If you use external USB drives or a NAS that's not configured as an exact mirror, you can choose to backup some portions of your main NAS on a different schedule than others, make hourly/daily/weekly/monthly snapshots, setup an elaborate system of rotating backup sets, etc.

The ReadyNAS devices include backup functionality sufficient for most simple backup schemes; there are addons for more complicated schemes. I backup my NAS to external USB drives using a combination of rsnapshot and the built-in backup features.

Aloise wrote:
One of my biggest concerns is related to reliability/security. I'm still trying to find the optimum setup for DATA + BACKUP with all the requirements mentioned before (media streaming for heavy content - FullHd videos, RAW photos... and accessible virtually from anywhere on the planet) and, of course, securely stored behind some sort of firewall or any other security solution.

For CPU- and memory-intensive tasks like video transcoding, the 516 looks like the right device to me, although I'm far from knowledgeable about those new OS6 boxes. I'm sure you'll get more dependable advice from someone who actually owns one of them.

For backups, any NAS or collection of USB drives large enough to hold all your data will do.