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Discussion Starter · #1 ·
I am getting close to putting together my first data storage server. I am currently looking at both FlexRAID and unRAID. From what I have read, they are very similiar.


I know FlexRAID is free and that unRAID is more polished. Other than that, does anyone know the functional differences between the two?


As a note, I am a storage server nub and know nothing about Linux and such.


Thanks!
 

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FlexRAID sits on top of an operating system, at least last I checked. It basically calculates parity based on data you provide it. It also doesn't have unified folder views as unRAID and WHS have.


unRAID is basically a stripped down Linux distro (Debian?) with custom code for the storage system and GUI. Assuming you did your research beforehand and all your hardware is supported, installation is as simple as unzipping files to a flash drive.
 

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because flexraid runs on an existing o/s you can install it on an existing windows computer. just add drives to the pc and go. you can still use the pc for other purposes. you might not need to add another box to the network.


if you don't already have the pc and you are building something for this purpose, unraid is added on to linux distribution.... that is, it is intended to have a dedicated linux box that doesn't do anything else.


for my purposes, having read the FAQs and some threads around the net, i would use flexraid.


read the faq and see if it describes you ...

http://www.openegg.org/faqFlexRAID.curi#basic

Quote:
FlexRAID™ Basic is suited for data that you only change a few times during the day.

If you continuously change your data during the day, every day, then FlexRAID™ Basic is not a fit for you.

You will have to wait for FlexRAID™ Live! or FlexRAID™ NAS.


Note that we are not talking about having an issue with continuously reading the data.

FlexRAID™ Basic will work just fine even if you read your data continuously 24/7.

It is just that FlexRAID™ Basic needs break periods where no data change is occurring to re-synchronize the RAID.


When I say "data change", I am not talking about adding new data files to the RAID as that action needs no break period at all.

Basically, you can continuously be writing new files to the RAID and FlexRAID™ Basic will run along just fine.

A good strategy would be to think about your data and separate the data you change continuously from the data you don't change continuously.

For almost all users, the data you don't change continuously will be larger and most likely the bulk of your data.

Once that's done, you can move the data that does not continuously change to be managed by FlexRAID™ Basic and move the other set of data to a much smaller RAID 1 or RAID 5 or NAS configuration and save a lot of money in the process.

my data is already separated as suggested.
 

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Quote:
Originally Posted by ilovejedd /forum/post/17041358


FlexRAID sits on top of an operating system, at least last I checked. It basically calculates parity based on data you provide it. It also doesn't have unified folder views as unRAID and WHS have.

However, you could use FlexRAID on WHS, and have the functionality of both.
 

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Quote:
Originally Posted by Darin /forum/post/17042041


However, you could use FlexRAID on WHS, and have the functionality of both.

Interesting. Last I checked FlexRAID, I don't think WHS was available. Or maybe it was but FlexRAID hasn't been tested on it at the time. unRAID was the only inexpensive option available and I needed something I can deploy right away. Too bad I'm out of cash (traded in my clunker so now, I'm making car payments). I would have liked to play with this.


Quote:
Originally Posted by cybrsage /forum/post/17042388


Hmmm...my data is segregated as well. I plan on storing my DVD and BR rips.


Does "no unified view" mean each hdd will be its own drive letter?

That would depend on how the underlying file system of your OS manages it. If using Windows XP, then yes, each drive will be its own drive letter.
 

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You can always have each drive as a NTFS folder nested on a root folder of your c:\\ drive.


Here's my set up:


c:\\movies\\Drive01

c:\\movies\\Drive02

c:\\movies\\Drive03

etc.


Each numbered "Drive" is actually a physical drive that no longer has a drive letter. There's no limit to the amount of drives you can add this way and all the drives are kept in a very organized way for FlexRAID to protect.
 

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I think part of the problem is that not many people have used both. I've been using unRaid for several years and have never had any problem. I have no reason to look at alternatives. I like that it is a simple OS run off a flash drive, so all drives are data. No worries about OS crashes/updates or other crap.


I certainly give unraid a thumbs up.


Brett
 

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I have Unraid the Pro version for a month now and I must say I cannot recommend it to anyone unless you are building it from scratch. If you have old hardwares, well wish you luck.


The problem that I have with Unraid is that it locks up the server every time I copy a large chuck of data over the network. I have to do hard reboot every time. Sometimes I feel like Unraid as my Vista. I do get helpful hints from Unraid forum members who are very knowledgeable but it's hard to diagnose a lockup issue.


edit:

Also, if you are into running media server like Mediatomb or PS3MediaServer, the Windows PS3MediaServer version is a lot better then the Linux version. I can run both Unraid and PS3MediaServer on the same box but I am not doing it because the better Windows version. So basically I am running 2 boxes. Now if I can get VMware to work on Unraid then that could be a different story. Then again, my Linux IQ is limited.


thanks,

~joy
 

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Quote:
Originally Posted by jouyang /forum/post/17043127



The problem that I have with Unraid is that it locks up the server every time I copy a large chuck of data over the network. I have to do hard reboot every time. Sometimes I feel like Unraid as my Vista. I do get helpful hints from Unraid forum members who are very knowledgeable but it's hard to diagnose a lockup issue.


I have been running unraid for a couple years with no problems whatsoever. I would highly recommend it.


If you have lockup issues, it is a hardware issue. Don't blame unraid because your hardware problems are hard to diagnose.


Willie
 

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Quote:
Originally Posted by cybrsage /forum/post/17041203


does anyone know the functional differences between the two?

I don't have either yet. But I've just finished gathering all the hardware for my server build, and I'm about to use a combination of WHS and FlexRAID. I can't profess to completely understand the inner workings and all the differences, but generally speaking, there are two significant operational differences, as I understand it:

1) unRAID essentiallyis the operating system. It's a customized Linux build, which is installed on a usb flash drive. The entire machine becomes a file server using RAID redundancy. FlexRAID can be considered more of a program installed on a PC (already running Windows, Linux, etc).


2) unRAID is a more typical RAID setup which builds parity on the fly. The current version of FlexRAID is considered "snapshot" RAID, in that it only runs when invoked, either manually, or by schedule (I believe most people have it running nightly).
In my opinion, for my needs, FlexRAID has the definite advantage on item 1. There are other things I'd like to have a server do besides file serving, and I'd rather not have two machines running 24x7. Since FlexRAID is just a program running on a PC, it does not care about what other things you may also have that machine doing. To the best of my knowledge, an unRAID box pretty much needs to do just that. I never did investigate the feasibility of putting unRAID on some type of virtualized server though, but even if that can be done, that comes with its own set of challenges.


On item 2, most people don't like the "non-live" aspect of FlexRAID. If you write data to a FlexRAID server, and don't manually invoke an rsync (parity build), then a hard drive failure between the time you wrote the data and the next automatic (scheduled) rsync could mean data loss up to the amount of data that you wrote since the last rsync. unRAID is calculating parity data live every time you write data. FlexRAID supposedly has a live version in the works, as well as a NAS version. But the current version is "snapshot".


That was almost a deal breaker for me, until I thought more about it. The most significant amount of data going on the server will be movie back-ups. If I back up a movie, forget to run rsync, and a drive failure occurs before the nightly rsync, it's not like I don't have the discs any more. The vast majority of data is still protected. At most, you should only lose data up to the amount that was written since the last rsync. Some people narrow their window of risk by scheduling rsync more often (like hourly). Another factor is that since you can run it in conjunction with WHS, WHS has it's own mirroring function built in. With WHS, you can pick and choose what data you want mirrored, and with FlexRAID you can pick and choose what data you want RAID'd. So the recommended practice is to have small frequently changed files protected by WHS mirroring, and large infrequently changed data protected by FlexRAID. And if you write a big chunk of data, just invoke an rsync.


Although I haven't seen any discussion on this, to me, it seems there would be a hidden advantage to "snapshot" RAID: it is completely transparent as far as data transfers go. Since unRAID is having to calculate parity and write to two disks for every single write, CPU cycles are being taken, and writes will be slower (as well as reads while another write is happening). Although I believe the vast majority of users are happy and get good performance, you do see the occasional "stuttering" post, so I can't help but think that the extra layer between you and the disks can sometimes introduce an additional variable that may have to be troubleshooted. FlexRAID operates more like a back-up program... while it's not running, it's just you reading/writing to the disks like normal.


One other advantage to the FlexRAID setup is that it's not restricted to protecting data on entire disks on the server. You can also include disks (or just specific folders) from other machines, as long as they are powered up when the rsync runs.


Someone may have to correct me on some of my points, but that is my understanding of the significant differences, as well as my thought process that led me to the direction I'm heading. Oh, and FlexRAID is free.
 

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Discussion Starter · #13 ·
Thanks everyone.


It seems that FlexRAID is what I want. I am going to be building a machine with the parts left over when I upgrade my HTPC (yeah, I have upgrade-itis, those new Intel i5 chips just look too good!), my CPU and motherboard will suddenly be freed up and available for the storage server.


I will be using Vista Ultimate (since I have a spare copy lying around) as the OS, so the OS cost is irrelevant to me.


I am an MCSE, so I have no problems with file shares. What I currently do in my HTPC (which has 4 HDDs right now) is to redirect the My Movies folder from my OS hard drive to the hard drive with all my DVDs on it. The other two hard drives have my BRs on it, and I just put shortcuts to each movie in the DVD hard drive. I then point all my applications which need to see any movie to the My Movies folder and they can see all the movies as if they were all there. It might sound like a pain to do if you have hundreds of movies, but I started out this way, so each rip just included the one extra step of the shortcut...a few seconds.


I can simply point the My Movies folder to the FlexRaid server where the DVDs are at and ensure the shortcuts are all good still and have the same result.


Again, thanks everyone!
 

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cybrsage,


it sounds like you are headed down about the same path i took a year ago.


some ideas i implemented that you might consider...


using mklink to create your shortcuts can be automated with cmd scripts. i wrote one that creates multiple "views" on drive c:.


the MyMovies meta data is stored in


C:\\MyMovies


each mkv/iso/mpg file has a folder under c:\\mymovies and the folder has a link to the file on whatever disk. ...


c:\\MyMovies\\\\movie.xxx --> x:\\_movies\\m\\movie.xxx


all of the drives with rips have a folder layout like this...


x:\\_movies

x:\\_movies\\a

x:\\_movies\\b

...

x:\\_movies\\z


collections are stored like...


x:\\dirty_harry



the script automatically goes through the folders on the drives and creates new links when files are added.


in addition to the MyMovies view. a unified folder setup is built in my videos folder. this view allows direct access to files using layouts (views) that my movies doesn't provide.


for example


videos\\_movies\\_all_mkv_files

videos\\_movies\\_all_mpg_files

videos\\_movies\\_all

videos\\_movies\\a

videos\\_movies\\dirty_harry

...


when the script runs it effectively merges the folders on all the separate drives into one under videos using mklink.
 

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Quote:
Originally Posted by Willie /forum/post/17043400


I have been running unraid for a couple years with no problems whatsoever. I would highly recommend it.


If you have lockup issues, it is a hardware issue. Don't blame unraid because your hardware problems are hard to diagnose.


Willie

I guess you didn't read my first paragraph. If someone is building a new box with the hardwares that are known to be working with Unraid, sure go for it. If you have old hardwares, they may or may not give you a lot of headaches.


Also, this same exact hardwares have been running XP for years. Sure, sometime I have to reboot it but that's Microsoft for you. For a Linux based OS that locks up your computer for copying data over a network and you have to do hard reboot. I think that's a bit hard to swallow.


thanks,

~joy
 

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Discussion Starter · #17 ·

Quote:
Originally Posted by oliverjg /forum/post/17043877


cybrsage,


it sounds like you are headed down about the same path i took a year ago.


some ideas i implemented that you might consider...


using mklink to create your shortcuts can be automated with cmd scripts. i wrote one that creates multiple "views" on drive c:.


the MyMovies meta data is stored in


C:\\MyMovies


each mkv/iso/mpg file has a folder under c:\\mymovies and the folder has a link to the file on whatever disk. ...


c:\\MyMovies\\\\movie.xxx --> x:\\_movies\\m\\movie.xxx


all of the drives with rips have a folder layout like this...


x:\\_movies

x:\\_movies\\a

x:\\_movies\\b

...

x:\\_movies\\z


collections are stored like...


x:\\dirty_harry



the script automatically goes through the folders on the drives and creates new links when files are added.


in addition to the MyMovies view. a unified folder setup is built in my videos folder. this view allows direct access to files using layouts (views) that my movies doesn't provide.


for example


videos\\_movies\\_all_mkv_files

videos\\_movies\\_all_mpg_files

videos\\_movies\\_all

videos\\_movies\\a

videos\\_movies\\dirty_harry

...


when the script runs it effectively merges the folders on all the separate drives into one under videos using mklink.

The My Movies folder I am talking about is the one inside My Documents. I actually use MediaBrowser instead of My Movies.


mklink does sound like it is a wonderful thing, I will look into it. When I finally build my storage server I will have to redo the shortcuts, and that will make it MUCH easier.


Thanks!
 

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I'd like to hear from anyone who's using flexraid and wrote some data right before having to reconstruct a failed drive. I just don't follow the Flexraid part when say you write data to drive X and then drive Y fails before you sync the parity. If Flexraid uses the data on the other drives to recontruct drive Y then the new data on drive X and the parity data will not combine correctly to reproduce drive Y. If you added say a 12gig rip to drive X right before the failure then there would be 12gig of bad data on drive Y after you recontruct it.


Sure, Flexraid could rebuild drive X if you just wrote to it and then it failed but how does it protect against a case of writing data to drive X (which, to me, seems to break the parity) right before drive Y fails?


Flexraid sure looks like someone started to create a program to emulate unRAID but just never got the live or real-time part figured out. Without the real-time aspect, it appears to me that the protection is broken until the parity is synchronized with any new data. It just strikes me that Flexraid is a "labor of love" development that hasn't yet fully matured into a product to protect many TB of data that get stored on some servers.


In the future, if Flexraid goes "live" then there might be the ability to create a server that can run other apps and also give a very cost effective way to protect all the stored data against a drive failure.


At this time I use unRAID. unRAID is a very simple OS that allows you to create a simple home build NAS device. I very much like the way it is simple and super reliable and it's really one less computer where I have to mess with the OS - just copy the files to the flash drive and go. I spend enough time messing with the HTPC to not want to also worry about the server OS. It's just cost effective way to store a lot of data. If you want fast read/write speeds or the ability to easily run other apps then you should look at other options.


Peter
 

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Quote:
Originally Posted by JoshDorhyke /forum/post/17046888


I'd like to hear from anyone who's using flexraid and wrote some data right before having to reconstruct a failed drive. I just don't follow the Flexraid part when say you write data to drive X and then drive Y fails before you sync the parity. If Flexraid uses the data on the other drives to recontruct drive Y then the new data on drive X and the parity data will not combine correctly to reproduce drive Y. If you added say a 12gig rip to drive X right before the failure then there would be 12gig of bad data on drive Y after you recontruct it.


Sure, Flexraid could rebuild drive X if you just wrote to it and then it failed but how does it protect against a case of writing data to drive X (which, to me, seems to break the parity) right before drive Y fails?


Flexraid sure looks like someone started to create a program to emulate unRAID but just never got the live or real-time part figured out. Without the real-time aspect, it appears to me that the protection is broken until the parity is synchronized with any new data.


Peter

Not quite sure what exactly you are asking but I will try this example:


Drive 1 contains: 1,2,3,4,5

Drive 2 contains: 6,7,8,9,10


I create a parity on Drive 3 (PPU#1) with two DRU's (#1 for Drive 1 and #2 for Drive 2) to protect the above two drives and their data.


I then change (add/delete) the following files on each drive:


Drive 1: 1,2,4,5,11,12

Drive 2: 6,8,9,10,13,14


So each drive lost a file but gained two files. The parity was not re-synched.


Now Drive 1 has failed and I use Drive 3 (PPU#1) to recover Drive 1 (DRU#1).


When the recovery is done I get this:


Drive 1: 1,2,3,4,5

Drive 2: 6,8,9,10,13,14


I have recovered the original files but lost the added files (11,12). If you create a DRU for each drive when you created your parity, you can recover each drive individually with a single PPU without affecting the other drives.
 

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Josh,

I posed the same question to the author last week. Yes, you do risk losing data on the failed drive, but only up to the amount of data that has changed (edited or deleted) on the remaining drives. That's why it's really best for data that rarely changes, like dvd backups. That's why my intent is to use it in conjunction with WHS file mirroring for the more frequently changed data (which for me, is generally small files, so the duplication doesn't mean a lot of extra HD space). Check out that thread and the replies.


Mickey,

Your example isn't necessarily true, at least not by my understanding. Since you have changed files 6,8,9,&10 on drive 2, the parity data would be based on "old" data. If you were to try to rebuild drive 1 by combining those files with old parity data, it wouldn't work. Since you didn't change file#7 on drive 2, you should be able to recover some of the data on drive 1. How much depends on how big file#7 is relative to the others. So FlexRAID probably wouldn't be a good choice for someone who changes files in between rsyncs as often as your example.


So, to Josh's point, this can be a serious consideration for someone until FlexRAID live is available. If ALL you want is a file server (or you don't mind having another server for your other needs), and you are storing files that are frequently changed, unRAID would be a better choice. But if your data is relatively static (or if you can use another solution for your non-static data) FlexRAID is a viable (free) alternative that has the advantage of being able to be run on a machine that is also fulfilling other needs.
 
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