I realize this may be a bit unfair to ask here but while I'm reviewing and assessing unRAID I want to compare it to other products and I can't find any.  Sure there are other NAS OS's out there but other then the hardware folks like Drobo or synology I can't find any software vendor who offers a product that provides unstriped, parity protected raid.  There are other implementations of raid but I can't find one that will allow me the easy expansion of unRAID.  Am I right or have I been errant in my google skills?

 

I am liking most of what I see in unRAID but I really want to be thorough before I commit to a build.

 

Thanks.

 

I realize this may be a bit unfair to ask here but while I'm reviewing and assessing unRAID I want to compare it to other products and I can't find any.  Sure there are other NAS OS's out there but other then the hardware folks like Drobo or synology I can't find any software vendor who offers a product that provides unstriped, parity protected raid.  There are other implementations of raid but I can't find one that will allow me the easy expansion of unRAID.  Am I right or have I been errant in my google skills?

 

I am liking most of what I see in unRAID but I really want to be thorough before I commit to a build.

 

Thanks.

 

As far as I know, unraid is the only software solution of it's kind.

I think there may be a couple other implementations that come close in some areas, but none I know of with a feature set that really compares point for point. It really is a fairly small niche market as it stands right now. The throughput is too low for a lot of enterprise applications (++$$$$), and the hobby market of compulsive software / media collectors is too small for the large companies to chase with a comparable product. That leaves other free or cheap products, and I'm not aware of any others with the large helpful community that unraid seems to keep. It really is a very low cost product, especially when you compare the price of the software to the total cost of a server hardware.

I think FlexRAID is as close as it gets, but it's not as good.

 

I've been trying to spread the word of unRAID to many. unRAID is definitely getting more popular (these forums are about 20x more active then they were 2 years ago). I see more and more unRAID builds popping up.

FlexRAID and Snapraid are probably the two closest in terms of technology both do unstriped parity. But neither are distributed as a standalone OS - yet. FlexRAID keeps threatening too but no sign yet.

 

FlexRAID is more feature complete and includes more parity protection features as well as storage pooling (similar to user shares. Not quite the same but similar). Snapraid is more barebones (by design) and just does the parity protection and points you toward using other tools if you need to layer features on top.

 

Thanks everyone.  I'll keep my focus on unRAID.

 

Thanks everyone.  I'll keep my focus on unRAID.

 

Welcome to the club

Believe unRAID is the best for my needs, and that is all that matters. It just runs and serves up my files.

 

http://snapraid.sourceforge.net/compare.html

Thanks everyone.  I'll keep my focus on unRAID.

 

Don't discount the others. They may work as well / better than unraid depending on your scenario.

 

Always personal preference / best tool for the job but unraid is far from perfect.

Thanks everyone.  I'll keep my focus on unRAID.

 

Don't discount the others. They may work as well / better than unraid depending on your scenario.

 

Always personal preference / best tool for the job but unraid is far from perfect.

 

Agreed.  But my big first step is finding the ease of expansion offered by unstriped RAID.  The ability to easily grow the array by adding any mix of drives is essential.  Everything else I look at either requires you to rebuild the array each time (NAS4Free, etc), offers JBOD (with no redundency protection or simply mirroring), or requires you to buy their hardware (Drobo, etc). 

 

I've not found a single other software solution other then unRAID.  I can beat up on all of the other features later.  But if I don't have this core as a starting point then I can only conclude that unRAID is singular in the marketplace.

 

Agreed.  But my big first step is finding the ease of expansion offered by unstriped RAID.  The ability to easily grow the array by adding any mix of drives is essential.  Everything else I look at either requires you to rebuild the array each time (NAS4Free, etc), offers JBOD (with no redundency protection or simply mirroring), or requires you to buy their hardware (Drobo, etc). 

 

Unraid will rebuild the *parity* but not the array when you add a new drive. So depending on what your issue is with rebuilding it may not help you.

 

Is your concern protection of data during the rebuild window?

 

I've not found a single other software solution other then unRAID.  I can beat up on all of the other features later.  But if I don't have this core as a starting point then I can only conclude that unRAID is singular in the marketplace.

 

Snapraid and Flexraid all allow easy expansion using differing disk sizes. And all will only have to update the parity once a new disk is added / included in the config in a similar fashion to unraid. They both, in effect have the same fundamental model as unraid. Bare filesystem disks + seperate parity disk(s).

 

The core differences are really that unraid works on the block level, not at the filesystem level and is also it's own complete OS. Flexraid and snapraid both sit on top of the filesystem (which is either good or bad depending on what you want) and are just standalone applications you install on top of your existing OS setup.

 

There are other bits 'around the edges' like cache drive / user share / storage pooling and how each offers them (or not) and the individual quirks of how they work. But if you're focusing on the core / fundamentals just now...

 

The feature matrix link on the snapraid website posted above is a pretty good and impartial look at things.

Let me rephrase my concern.  Other systems like NAS4Free require you to build a new array, then move your data, then discard your old array.  So, if I've got a 5 x 2tb array and run out of space I've got to go out and buy SIX new disks and something to put them in.  Then I have to build a new array.  I can't just buy ONE NEW DISK and add it to the existing array.  I believe that unRAID will let me do exactly that.

 

So, I get "enough" data protection from the parity drive that I can sleep at night AND I know that I can take advantage of sales at Bestbuy to grow my array when I need to.

 

Flexraid, snapraid and unraid will all do expansion with no loss of existing data using any size of drive. You will have a window of lesser protection whilst the parity is in flux however.

Flexraid, snapraid and unraid will all do expansion with no loss of existing data using any size of drive. You will have a window of lesser protection whilst the parity is in flux however.

 

OK, that's what I thought - Add the drive and then rebuild the parity but but be aware of the exposure while rebuilding.  I think flexraid drops off of my list because I want a complete OS solution that I can boot from a jumpdrive.

 

Thanks again.  More info is always appreciated.

 

 

Agreed.  But my big first step is finding the ease of expansion offered by unstriped RAID.  The ability to easily grow the array by adding any mix of drives is essential.  Everything else I look at either requires you to rebuild the array each time (NAS4Free, etc), offers JBOD (with no redundency protection or simply mirroring), or requires you to buy their hardware (Drobo, etc). 

 

Unraid will rebuild the *parity* but not the array when you add a new drive. So depending on what your issue is with rebuilding it may not help you.

 

This is not true. Parity does not need to be rebuilt when adding a new drive. Cleared drives do not effect parity.

ah fair enough, it's been a while since I've added one. Perhaps I'm confused and it's a parity check that's triggered by adding a new drive?

No automatic parity check is done when adding a new disk. This happens after an unclean shutdown. Parity generation happens if a parity drive is added late, but this is a bad idea.

hmm ok my mistake. I guess it really had been too long since I added a disk!

The long delay in adding a new disk to unraid isn't parity generation, it's writing zeros to the entire drive so parity is maintained when the drive is added to the storage pool. Joe's preclear script is designed to do that lengthy operation in the background without keeping the array offline for the entire time the zeros are being written. Along the way, Joe decided that this was an ideal time to run some tests on the drive to make sure it was good, and we now have his preclear script that not only zeros the drive and preps it for a quick insertion into the drive pool, it also provides a good indication of whether the drive is ok or not. Multiple preclear passes give you an extra confirmation that the drive should survive in the array. I would never add a drive that hasn't passed at least 2 preclear cycles, new or not.

... but unraid is far from perfect.

 

Boof, care to share your view on any of unraid's shortcomings?