unRaid or FlexRaid ?

Unfortunately, I can't give you a comparison, as I've used FlexRaid without using UnRaid, but, having said that, I was completely unfamiliar with the different RAID-esque possibilities and ended up going with FlexRaid for my 24-bay server, and have found it pretty darn simple to work with.

Then again (knock on wood), I haven't had a drive failure yet. So I guess I can't speak to its reliability for swaps/restores yet.

Why Raid at all?

Well, if you want a server with lots of storage you need a setup that allows you to string multiple hard drives together.

FWIW, I'm in the same boat as the FlexRaid user above, except that I've been using unRAID for about five years but never tried FlexRaid. I believe there are trial versions of both apps so give them a try and see which you like best. My current setup consists of 20 drives with a total capacity of 23.75TB. The latest version of unRAID now supports up to 24 drives, IIRC. Simple to set up, simple to use, and simple to maintain. Version 5 now supports multiple plug-in apps, like Plex Media Server and many others.

Then why string them together? Do you have files larger than 3TB? With RAID you're always in danger of losing everything.

To add a little context to my advice here is my current server setup:

Windows 7 Pro with 1 O/S Drive, and 6 hard drives ranging in size from 1.5 TB to 4 TB. The CPU is a core 2 quad, and the system has 6 GB of ram.

On the O/S drive I run flexraid. My parity drive is one of the six previously mentioned drives. I also have an external 4 TB drive to back up items I don't have on DVD, Bluray etc. On the O/S drive i also have a VM running which handles downloads from various sources.

Basically I prefer this setup because it offers a lot of flexibility in one box which you will not get with unraid. I am also terrified of using a USB drive as a system drive which means unraid isn't an option for me.

Correction --- with hardware Raid you are in danger of losing everything.

This is absolutely not the case with some of the software raid options which is just one of the many reasons they are much better for a HTPC server.

While I haven't used Unraid, from what I know, Unraid and Flexraid seem to be functionally very similar. The big decision is whether you want to install software raid on top of an existing operating system. Flexraid lets you do that. For instance, I use a WHS2011/Flexraid combination. If you just want a dedicated NAS box, and don't need Windows programs or Windows Server features, then Unraid should work well.

Both are great.

Unraid is potentially more expensive. Also relies on a USB/Flash drive for the OS (both good and bad potentially).

FlexRaid can add empty, partially full or completely full drives to the array.

Like Assassin indicated, unRAID is a software RAID system and is not hardware RAID. UnRAID uses a parity drive that prevents data loss if you lose a single drive in the array. Of course, if more than one drive fails simultaneously then you'll lose data on all drives that failed. One thing I like about unRAID is that any files you copy to the array get assigned to a single drive in its entirety and doesn't get divided and stored on multiple drives. This way you don't lose bits and pieces of all of your media that's spread across the array. You only lose whatever movies or videos that are isolated to the failed drive.

I also like that I can assign shares and map the shared folders as a single entity. For example, I have four shares set up on my server - HD.DVDs, DVDs, Videos, and Misc. When I copy a ripped movie over to one of the shared folders, unRAID finds the drive with the largest available space and puts it there. The actual location of the files are invisible to the user as all similar files show up in the shared folder, regardless of the drive where they're physically located. You can map each individual drive if you want to see what's on each one.

The idea is to have a server for central storage of all types of media that can be accessed from any computer on a home network. I've got several HTPCs with XBMC installed. All of my movies have been ripped to mkv files for ease of handling and playback. I can combine any of the shared folders on the server in the XBMC video library so they all show up in one huge list. It's pretty simple to spot which ones are DVDs and which ones are Blu-Rays just by the type of audio indicated on the metadata window that appears when each movie is selected as you scroll through the list.

Are you looking for data redundancy or drive pooling? For the data redundancy, neither setup is going to get you much over straight folder duplication. In the 1TB + 1TB + 2TB setup you'd have to use the 2TB as the parity drive, so you'd only have 2TB of drive space. With the 2TB + 3TB + 3TB, you'd be using one of the 3TB drives, leaving you 5TB of space, or 1TB extra over straight folder duplication.

I use flexraid with 2 1TB and 5 2TB drives and its great. About once a week or so, the parity doesn't update properly, but I think that it is something else running at the same time that is interfering.
I did have some difficulty getting the FlexRaid shared folders to show up in my HomeGroup though (didn't show, then had duplicates), but eventually it sorted out.

I like not having to deal with multiple folders on different drives for the same content. I have about 7TB worth of DVD and Blu-Ray rips. Its great to have just one My Movies folder rather than 4 My Movies folders on 4 different drives, each of which I have to tell each of my HTPC's to recognize.

Yep. Pooling. Another thing that FlexRaid has built in that others do not.

Take a look at SnapRAID:

http://snapraid.sourceforge.net/

It is free and works well. It is not as polished as FlexRAID though. If you want a GUI for it, you can get a basic one here:

http://elucidate.codeplex.com/

It appears the GUI has been abandoned, though it will work with all versions of SnapRAID.



As for FlexRAID, I stopped using it when it went pay, but I did use it to recover a failed drive. It worked perfectly. I would have no hesitation recommending FlexRAID to give a layer of protection for your drives.

If you don't want redundancy then forget either. Their point is parity backup. If all you want to do is pool drives, you can do this natively in windows 7 (all versions may not support this feature) disk manager by converting each drive to dynamic mode and making them an extended drive of a virtual folder. However, once you go dynamic mode another os can't read the drive, so make sure to image your os in case you need to restore or create a backup of the disk manager config.

If you want parity with flexability, flexraid wins. It runs on an os so you can use the system for anything else. The only thing unraid can do over flex (unless flex has released it now...I haven't updated in awhile) is live parity instead of snapshot.

I've personally restored a 1TB drive with flexraid over a year ago and I haven't noticed an issue. Believe me, when one of your HDs crash (it isn't if - it's when!), you'll be wishing you 'wasted' one of your largest drives as a parity to rebuild it for you. The amount of time and effort it would take to re-rip all those discs, alone, is worth the investment.

Sent from my SPH-D700 using Tapatalk 2
Edited by jrwalte - 9/13/12 at 8:56am

The guy built an excellent piece of software and it is worthy of its cost. I was more than glad to pay for it, and was thankful to finally get away from the expiring beta releases. All this FlexRaid talk makes me want to check out the latest release and see if I want to update. The pay version has been self sufficient and reliably sending me those parity backup success emails every day for over 6 months. First time I had to log in and touch it was last weekend when I added a new drive. 3 minutes later it was in the parity and in the pool.

I nearly didn't go with FlexRaid because of the way the expiring beta releases were handled. I get that he wanted to eventually get paid for his work, but there was no notification (at least on the version I was using) that you version had expired. I assumed it was continuing to update until suddenly I couldn't even log into it. Really pissed me off. Ultimately FlexRaid was the best solution for what I needed, but I looked long and hard first.

FlexRaid wasn't around when I built my unRAID server and I don't believe SnapRaid was either so my choices were somewhat limited. I like the fact that unRAID boots from a flash drive, freeing up 100% of my available hard drive space for storage. I'm not sure what you'd want to use a server for other than storing and sharing files since that's sort of the point of having a server. I would assume that since someone would be building a FlexRaid server there must be at least one other PC in the house for performing the usual PC tasks. My server resides in a small storeroom that's not exactly suited for using it as a sit-down PC. I'm not sure I like the idea of having to purchase an extra OS license just to use FlexRaid, plus the fact that I'd be sacrificing storage space as well.

Anyway, there are several threads discussing the pros and cons of all three server apps so pick the one that suits your needs and go with it. FWIW, I had a drive failure a while back and never lost any data due to the ability to rebuild it from parity.

One thing I noticed about FlexRaid vs. unRAID is that you have to completely uninstall an existing version before you can upgrade to a newer one. With unRAID, you simply connect to your flash drive (it maps just like any other drive) and copy over a couple of files and reboot. It doesn't get any easier.
Edited by captain_video - 9/13/12 at 11:14am

I've used unRAID for a long time, tried out FlexRAID, and am currently using SnapRAID. They all have their pros and cons.

Realtime protection:
* unRAID and FlexRAID offer realtime parity
* both only offer a single parity drive solution at this stage (both have plans for dual parity setups in realtime but who gets there first is anyone's guess)
* FlexRAID realtime is not as stable as unRAID for realtime parity (it does not handle anything that does not pre-allocate, and it hates Teracopy - author is aware of this issue)
* Only unRAID offers simulated drive failures -- all other solutions won't offer up your lost files until you do a full repair

Drive pooling
* FlexRAID and unRAID again both offer this functionality (optional in flexraid, but mandatory for realtime raid)
* unRAID allows you to both view and operate on the individual drives that comprise the array without impacting realtime parity. Others only allow this functionality in Snapshot mode.

Shares
* FlexRAID and unRAID handle sharing via their interfaces
* SnapRAID etc. does sharing via the underlying OS

Performance
* FlexRAID is the fastest for realtime
* unRAID can incorporate a cache drive
* I'm not sure of what the speed is like comparing snapshot parity between FlexRAID and SnapRAID (but am perfectly fine with the performance of SnapRAID)

Support
* unRAID wins this by a country mile, the community is the most active and very helpful
* SnapRAID and FlexRAID are also helpful, but suffer from lack of community participation

SnapShot protection
* FlexRAID has no limit on how many parity drives you can employ
* SnapRAID is limited to 2, but have plans for 3 drives in the future (probably distant future)

File integrity
* unRAID does not have this feature
* SnapRAID does checks on the block level
* FlexRAID does checks on the file level

For me the ideal solution would be:
* At minimum - dual parity real time protection
* At minimum - file level integrity checks
* No striping
* Drive pooling
* Live protection (aka simulated failures ala hardware RAID functionality)
* Nice to have some form of undelete or versioning perhaps - not sure how this would work in realtime parity though

As for why realtime over snapshot? Beyond the initial parity creation, realtime is more energy efficient and more foolproof. It doesn't care about having a block of time when nobody is using the machines to ensure a successful sync.

Other possible reasons for server: ftp, internet video streamer/transcoder, dvr recorder (so all pcs can stay off), media browser scraper, commercial scraper, video converter...many other reasons could be thought up. Does everyone need it? No. But it does offer more flexibility for the future.

While you have to uninstall flexraid to update, it doesn't lose your parity/pool config. At least not anymore.

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Best of luck with FlexRAID, it is the most complete of the three and with a decent 14 day trial period, you can get a good idea of how it works. Snapshot raid on FlexRAID appears to work well from all reports, it's just the Realtime functionality which may or may not be problematic depending on your uses. If using realtime raid, make sure you test and re-test your hardware for stability and get that all ironed out first. Each time the array encounters a problem, it usually requires a check and reconcile etc. and that can take quite a bit of time.

I'm not done with FlexRAID yet, will re-evaluate as time allows and will definitely be checking back on things when Brahim unleashes NZFS.

If you go that route, be sure to check out their tutorial on making your drives share work. There's a specific method for doing it in WHS2011.

I think this got touched above, but the big benefit is not needing to keep track of what drives are full/empty and what drive has what on it. Think of it like this, you can get big drives today, say 3TB that will hold a lot of stuff. So you put your pictures, movies, music on it. Works great, until you fill up that drive, so then you buy another drive, what do you do. Well without pooling you've got a couple options, one is you can copy say all your movies to the new drive leaving the pictures and music on the other. OK, not too bad, if you want your pictures or music it's on drive 1, movies drive 2. Not bad. Then you fill up drive 2 with movies, what now, get a new drive, and what, put all the new movies on the new drive? How long until you can't remember whether a given movie is "old" on drive 2 or "new" on drive 3.

Basically before too long, when you get a reasonably large number of drives, it becomes "impractical" to manually manage what goes on, and what lives on which drive. A pool makes it transparent to the user, everything is on the pool and you just go to the pool for everything.

Now granted, frontends like XBMC/MM/etc can pull media from multiple places so from a playback perspective you can hide that complexity, but you still have to deal with it when you add new media.


Oh, I disagree completely, at least once you get past a drive or two. For any n drives worth of data, parity will save you n-1 drives. For 2 data drives that's not a big deal, 2-1 = 1 drive, but when you get up to more like 4 drives, that's 4-1 = 3 drives saved. I've got 6 data drives in my unraid so parity saves me 6-1 = 5 drives, that's not insignificant.

Another way to look at it is with folder duplication you lose 50% of your space to redundancy, with parity you lose n-1 drives, so for four drives you only use 25% for redundancy, for 8, it's only 12.5% (now it might be a little more when you start using different sized drives).

Just consider how long it will take you to re-rip/reorganize 1, 2, 3, 4TB of data if/when you lose a drive. It's that work that those of us that run redundant storage solutions are trying to protect. All my media is replacable from the original discs, but there's work involved in doing that. I value my time higher than the $100-200 for the extra drive required for redundancy.

This is what I do to manually handly all my files spread out over five drives:

1. On each of the drives I create a folder named after the genre of what I will put in it. Chick Flix, Religious, Old Movies, SciFi, etc. I put all the related movied into it. I also have a folder just called Movies for the ones that fall outside the easily recognizable genres. For Star Wars, it is obviously in SciFi - then I have a folder in SciFi called Star Wars and all the movies are in their own folder in there (all three of them - there are actually only three Star Wars movies!!!!).
2. On the parity drive (not one of the five I mentioned), I put a shared folder called Movies. I put a shortcut to all the other folders inside that shared Movies folder.

I can easily get to all my movies by simply surfing the one shared folder. Each subfolder takes me to the proper hard drive. Easy breezy covergirl.

Yes, your parity drive must be at least as large as your largest other drive. It can be larger, but it cannot be smaller. If you upgrade to 3 TB drives, you will need at least two - one for the data drive and one for the parity drive. It is the biggest limitation to RAID4.

What I do is a cascading upgrade. I upgrade my parity and one drive, then use those two drives to replace two smaller drives. Right now, my parity is 2 TB, ! have (2) 2 TB data drives, (2) 1.5 TB data drives, and (1) 500 GB data drive. When I upgrade to 3 TB, my parity and one drive will become 3 TB and the 500GB and (1) 1.5 TB will be replaced by the (2) 2 TB drives. I still have one open SATA port (8 on the motherboard and 2 on an add in card), so I might keep both 1.5 TB data drives, replace the 500GB data drive, and add the released 2 TB drive as an additional drive. I currently have:

(1) SDD OS drive
(1) 1 TB recorded TV drive
(1) Dual HD-VD / BluRay drive
(1) 2 TB Parity drive
(2) 2 TB Data drives
(2) 1.5 TB Data drives
(1) 500 GB Data drive

For a total of 6 TB of data being protected by SnapRAID (the OS and recorded TV are not protected).