Debating: unRAID or FreeNAS - More information in thread

[thecoffeeguy]

I know this is my sound like a loaded threat title, but I am really at a crossing roads here and need to make a decision pretty quickly.

Let me provide a little history here.

 

I had a home lab disaster recently. In short, I had two internal drives in my laptop, both SSD's. My second SSD drive which held a lot of my VM's, up and died after two months of using it (still trying to figure out what happened and im still shocked.) On top of that, when I went to restore my VM's from my backup dive (external drive), that was dead. It was the ultimate double face palm moment.

 

Fast forward to today. That said, I am need to architect a better solution for storage and backup. It will be critical for my home lab.

 

What will it be used for:

 

Items I am thinking about using it for:

 

-backups. backup backup backup. Reliable backups of my virtual machines.

-Building on backups, I currently run everything from my laptop, but that is going to migrate to a ESXi box I just created. Shuttle box. The caveat here is I am trying to decide if I should just run the VM's on the ESXi box on the local drives, or should I mount them via NFS from the NAS device.

 

Decisions I am looking at and trying to kick around.

 

As I started to look for solutions, items like Drobo and Synology were way to pricey. I figured I would build my own.

 

I first started looking at FreeNAS. Did a lot of research and then bought a few pieces for my NAS (mobo, cpu, memory.) Bought supermicro board, Intel CPU, 8gigs of ECC memory. All for about $280. Still need case and drives and eventually, more RAM.

 

Those pieces should be delivered this week.

 

Now, as I was researching this, a friend told me to look at unRAID. I started to read up here learning more about unRAID and now I am looking what route I should go.

 

Differences so far that I have picked up (bare with me, this is rushed.)

 

FreeNAS - heavily uses ZFS (and im still learning ins and outs of ZFS). Loves memory.

unRAID - free for 3 drives, more drives has a cost.

 

Now I know there are differences between the two as far as storage, building out volumes, adding storage etc. that I want to learn more about.

 

That is pretty much a overview of what I am looking for.

 

My ultimate goal is to have a very ROCK SOLID STABLE NAS. I put emphasis on that, because I cant have losing VM's like I just did recently.

Performance is good, but not super critical. If i decide to mount some NFS points to the ESXi box, as long as it is pretty good and stable, I should be set.

 

I appreciate the feedback on this.

Just wanted to hear some suggestions based on my needs that I laid out above. Pros and Cons, things to consider etc.

 

much appreciated.

 

Thx

 

TheCoffeeGuy

[vl1969]

I think I chime in 

 

first and foremost you need to understand that UnRaid is NOT A BACKUP solution.

well at least it should not be your only means of data preservation.

 

there is only a few things that differentiate unRaid from all other similar products :

 

#1. unraid is a  real time parity based multi hard drive NAS type setup . with unique capability of using different size drives in a storage pool.

what is unique about it is that it provides real time protection unlike for example  snapRaid which also capable of pooling different size devices and using parity but provide protection in a way of snapshots, not real time.

 

#2 and this one is also unique feature is that unraid unlike FlexRaid ZFS in general does not work like regular raid or storage pooling software except maybe again SnapRaid or tRaid. UnRaid does not stripe your data among devices in the pool.

it simply places the data on the single device. thus if by any chance you have a multiple device failure (a situation that can not be recovered from with a single parity setup) you only loose data on the devices that failed, not the whole pool.

the rest of the drives can be pooled form the system and data copied to a new location.  so if you have 5 2TB drives on unRaid (not counting parity)  for total of 10TB and 2 fail you only loose 4TB not the whole 10TB as with regualr raid setup , not sure about ZFS based systems but I don't think they have this capability and you would loose the whole 10TB.

 

so it is up to  you to  decide  what you need...

 

 

 

[thecoffeeguy]

hey there. thanks for the reply.

 

Thats good info.

Maybe I overstressed the importance of backups. Probably more importantly, a reliable storage piece. Meaning, reliable hardware top to bottom. I am ok with spending more money for better hardware to ensure stability.

 

That helps  out. I definitely like the ability to add different size drives to a setup.

 

Being able to store data to recover from is important. ZFS sounds very interesting, but very resource intensive.

 

Maybe I am reading it wrong, but if I have 4 drives in a setup for unRAID. If so my VM's are stored on disk1 and disk1 dies, how does unRAID allow me to recover from that? It sounds like i need to read up some more, but im just a tad confused here.

 

Appreciate the feedback.

 

Cheers,

[bkastner]

Maybe I am reading it wrong, but if I have 4 drives in a setup for unRAID. If so my VM's are stored on disk1 and disk1 dies, how does unRAID allow me to recover from that? It sounds like i need to read up some more, but im just a tad confused here.

 

Appreciate the feedback.

 

Cheers,

 

You can recover because of the parity disk. If you lose a disk unRAID is able to figure out what data was on it using the parity bits. You can then add a replacement disk and unRAID will rebuild the disk just as it was before it died.

 

You can still access data on a non-existent disk in this scenario, but it's slow.

 

Basically with parity it figures out the parity bit for each sector of the disk using binary. Since the value needs to be 0 or 1 the parity disk can figure out what the missing data is, but it needs to be calculated on the fly if the disk is missing. Easy example is 1+1+1+1 is 4 (in binary it would still be one, but you get the idea). If one of the disks is missing then you have 1+1+?+1=4 where the ? is the missing disk. Parity can figure out what that missing bit is and present it back to you. Once you put in a new drive parity will do the same - it will know there should be a 1 in that sector so it will write it.

 

As you can imagine if it needs to do this for every byte on an entire disk on the fly it's a bit slow, but it works.

 

[vl1969]

hi there,

 

the unraid uses Parity to validate and protect from single device failure.

basic free setup uses 3 drives 2 data 1 parity.

if you loose parity drive your data is safe, unprotected but safe.

if you loose single data drive you can replace the failed drive and unraid will rebuild the data on the new drive using the good drive and parity to recover.

here is the WiKi  link

http://lime-technology.com/wiki/index.php/Parity

and here  http://lime-technology.com/wiki/index.php/FAQ#How_does_parity_work.3F

 

 

also if I would you I would not run VMs from the array space.

I would dedicate an unprotected space  somewhere else and stored the VM snapshots as a backup on array.

since VM files do change running from protected array might be slower.

but it might not be an issue for you per see..

 

[thecoffeeguy]

That makes a lot of sense guys.

Appreciate it.

 

TCG

[jimmysticky]

Did you post your question in the freeNAS forum too?  One of the features of freeNAS' ZFS filesystem is the ability to self-heal files. I only understand the very basics of it, but it has to do with the ECC memory too.  People rave about the benefits of zfs over there.