Ok...so here's what I'm working with. I've got three 4 drive drobos filled with 3 tb drives chained through firewire to a mac mini running plex. Well, one of the drives in one of the drobos went out. When I replaced it, the drobo entered an endless reboot loop. I'm hoping to offload the data from a working drobo then put the drive set from the bad drobo in there to pull that data. So my plan is to build a proper server. I've got all the parts on their way to build a 16 drive box. Included with the parts are four 3 tb drives to start the transfer. I want to fill the drives from a drobo then add the drives in that drobo to the box. I'd repeat the process for the three drobo drive sets until I have all 16 drives installed in the box. What I haven't decided on is the software to use. I really like what I see in unRaid with one exception, only one parity disk. Assuming I set up a cache drive, I'll have 14 drives with one parity drive. I'd prefer at least two parity drives just for added security. With a cache drive, I can always sacrifice it temporarily to instantly replace a failed drive while I wait for a new drive to come in. That seems like a pretty good solution but, again, not ideal.

 

I know flexRaid isn't a popular topic here but that's my other option. I can set up 2-3 parity disks but I also lose a drive slot for the system drive. I also get the added benefit of having a full GUI based OS. To some people, the full OS might not be ideal but I'm not one of them. I know there's an added cost for the OS (probably Windows) but that's not a big concern for me.

 

So my question. With my situation, why would I choose unRaid over flexRaid for running a media server with good support for possible drive failures?

I also had an issue with a Drobo where a single drive failure meant that all data on it was inaccessible!  Luckily in this case the data on that particular Drobo was available from my backups.  This Drobo experience put me off any system where the loss of a single drive would make data on other drives in the same system inaccessible.

 

The thing I like about unRAID is that each drive is a self-contained file system so failure of one drive does not affect other drives.  This also means that a single drive can be removed from the array and connected to another machine and its data accessed. 

 

The issue of multiple parity drives is one that has been raised quite a few times.  We keep hoping that support for an additional parity drive will be introduced at some point.  It is on the roadmap as a potential new feature, but there is no ETA of when/if it might become available.  It is certainly not in the 6.0 release that is imminent, but until that appears a

 

The fact tht each drive is a self-contained filesystem comes into its own in complex failure scenarios if for any reason the built-in unRAID facilities for reconstructing a failed drive fail (rare but possible) as long as one always does a rebuild onto a spare drive and keep the ostensibly failed drive intact.  this is because drives in fact rarely completely fail so much of their data can be recovered if they can be handled outside the array.

I was a Flexraid and then transparent raid user. All I really wanted was a storage device for my Documents, movies and photos. The two parity drives was important to me at the time but I had so many issues with windows home server and bugs in T-Raid that I moved to unRAID. I had already had help on the unRAID forum in building my server as this was non existent on the Flexraid forum. I can honestly say I'm so glad I made the move. I don't have one windows PC in my house now just unRAID and macs. I backup my unRAID data to external hard drives as no NAS or Server is a backup solution, and in the years unRAID had been going only a few users have had two drives fail at once. As long as you watch out for errors and do parity checks it minimises the risk. T-raid used to take twice as long to do parity checks and I had so may issues with WHS I was spending more time bug fixing. Just using cache dirs and having drives that I may only use once every 6 months spin down makes it worth the cost.