FreeNAS best option for me to replace RAID5?

A

akira181

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Currently I'm running Windows Server 2008 R2 in RAID5. The OS is a lot more than I require for my needs and I recently learned a RAID5 setup with 6x 1TB disks will have a high chance of failure in a rebuild due to bit rot and URE. So I've spent the last few days reading and I think FreeNAS will meet my needs but there's a lot of information jumbled in my head so I thought I'd post and ask.

Basically I have an old home computer that I modified to be my NAS. I use it to consolidate all my files from multiple devices into one place (pictures, documents, work files, music, movies) and sometimes use it to stream movies to my TV.

I'm looking for a NAS OS that will have some redundancy (doesn't need to be bulletproof as I backup important stuff to an external HDD) and can double as a HTPC. I see FreeNAS has Plex for streaming and ZFS for redundancy, so it looks like it might be able to do all I need.

My hardware is as follows:

Mobo: ASRock K10N78D
CPU: AMD Athlon64 X2 5600 (2.8 GHz)
RAM: 4GB DDR2
HDD: 6x 1TB SATA2 + 180GB IDE boot disk

I know AMD is not recommended for FreeNAS and I'm a bit on the low side for RAM (I can always hit up ebay for upgrades). Apart from these two flaws, is FreeNAS best for me or is there something else I should consider?
 
You really want ECC if you want to take advantage of the reliability FreeNAS & ZFS.
 
I agree but the price of ECC RAM is too expensive for my budget, plus I would need to buy a server motherboard. The chipset in my motherboard is an NVIDIA nForce 720D and I do not believe that supports ECC memory,

Since the non-ECC ram I'm using is only a few years old and has run through memtest86+ with no issues, I like to believe that the chances of corruption would be low, especially since I would not be writing large amounts to the NAS very frequently after initial setup.

Plus, my important documents would be backed up to an external HDD fairly frequently so, in my opinion, my chances of corruption are low and the risk lessened by my external HDD.
 
If you are trying to protect against bitrot, you won't be able to do it effectively without ECC.

If you run a scrub on your volume and a bitflip occurs, the scrub will destroy your data. You'd be trading one problem for another. I'm sure you know, but a bitflip can occur even with perfect RAM.

However, ZFS does handle UREs better as the whole volume doesn't get destroyed if a URE occurs during a rebuild.

If you plan on running ZFS you will want 8GB minimum, and I would recommend running RAID-Z2.

I highly recommend FreeNAS if you want something to play with. I have Transmission, Plex, OpenVPN, ownCloud and CouchPotato running on mine.

Edit: Here's some good reading in case I can change your mind: http://forums.freenas.org/index.php?threads/non-ecc-and-zfs-scrub.16515/
 
I was worried that 4GB RAM might be a touch low, DDR2 RAM is so expensive, it's like the price never dropped since release. Might run FreeNAS for a while and see if I'm happy with the performance before spending cash on another 4GB (would love to have 16GB, but budget comes into it again).

ZFS is still rather new to me, so this is the first time I'm reading about scrubs in detail. It does sound pretty bad that it could snowball corrupt my data. Is it not possible to do a backup of the pool/parity data so in the event of a snowball corruption, I could recover the data from a backup? That way I could backup the pool on my external HDD before manually running a scrub.

I've read this article, http://blog.brianmoses.net/2014/03/why-i-chose-non-ecc-ram-for-my-freenas.html , and it does highlight the risks and such, but it sounds like my intended use is similar to his, so I might be able to get away with it.

I mean, I'd like to get ECC RAM and a low power server mobo/CPU but it's just a budget issue right now. Plus, everything important will be frequently backed up to an external HDD (and the most current items will still be on my main computer), so if I do get major corruption, it's not the end of the world. Just an annoyance and an indicator that it's time to get ECC
 
just had a thought. How does ZFS handle expansion and disks with different capacities? As in, currently I have 6x1TB HDDs. What if one died and I replaced it with a 2TB disk? Does 2TB get added to the pool?
 
akira181: Sounds like you're aware of the risks and have a solution, I'd go for it.

Regarding adding drives, lets say you had 6x1TB in RAID-Z2. If you replaced 1 of them with a 2TB, you would still have 4TB available (2 drives lost to parity). However, if you replaced all 6 of them with 2TB drives one at a time, your pool would expand to 8TB.
 
ECC RAM is no more or less important using ZFS than any other filesystem and you do not need 8 GB of RAM.

ECC RAM will increase the reliability, yes, the same as with any filesystem.
More RAM will increase performance, yes, but not for mostly static data, which I assume this is. And seeing as you're running this on very old hardware, I doubt you have a requirement for very high performance.
 
akira181 said:
I agree but the price of ECC RAM is too expensive for my budget, plus I would need to buy a server motherboard.
Click to expand...

Actually, not exactly.

I have two machines now running ECC with consumer level motherboards. I have a Rampage III Gene running 48GB (6x8) RDIMMs and a super cheap ASRock 880GM-LE (a $50 motherboard) running 2x4GB ECC UDIMMs. The 880 has a Phenom X6 1075T that I got off of eBay for $83 over a year ago, and the two 4GB ECC UDIMMs I just bought for $95 shipped from Newegg.

Just giving some information and options :)
 
Talonz has it right: if bitrot is your worry, then you can't truly cure it without ECC. Since bits can flip on disks, as well as in RAM, it's really a matter of covering both bases, or neither. If you aren't able to make the leap to ECC hardware yet, you're probably better just holding on to your RAID for now.

You can indeed run ZFS without ECC and not set up any scrubs. It would prevent the dreaded "scrub nuked everything", but would permit trouble to brew silently, kind of defeating the purpose of ZFS.

You don't strictly need 8GB, but performance is known to suffer with less since it doesn't leave much room for the ARC. 8GB is generally recommended as minimum.

I vote you save up for the right hardware and WangChung has shown it can be done economically. 6 disks would be perfect for a RAIDZ2.
 
akira181 said:
I agree but the price of ECC RAM is too expensive for my budget, plus I would need to buy a server motherboard. The chipset in my motherboard is an NVIDIA nForce 720D and I do not believe that supports ECC memory,

Since the non-ECC ram I'm using is only a few years old and has run through memtest86+ with no issues, I like to believe that the chances of corruption would be low, especially since I would not be writing large amounts to the NAS very frequently after initial setup.

Plus, my important documents would be backed up to an external HDD fairly frequently so, in my opinion, my chances of corruption are low and the risk lessened by my external HDD.
Click to expand...

It is true that RAM rarely fails on it's own when in a system, but the consequences of RAM failure are pretty dire on any ZFS based system (like FreeNAS or Napp-IT).

RAM Failure will lead to silent corruption of your data. And don't think that offline backups will save you, as your automatic backups will back up the corrupt data as well...

I can't recommend ZFS highly enough, but you REALLY want ECC.
 
I agree with the above, if you can forego the latest and greatest you can get proper server hardware on the cheap.

I got my sealed new Supermicro X8DTE motherboard for $150 on eBay, and my dual 6 core Xeon L5640's are going for ~$60 each on eBay right now. The most expensive part of my server build was the Norco RPC-4216 case.

If you don't need dual socket or 6 core Xeons (which you won't if it's a dedicated bare metal FreeNAS box) these prices are likely much lower.

Another option is going with consumer AMD parts. All the FX chips support ECC natively, you'll just need to find a motherboard that does as well (There are a couple of AM3+ Asus boards that do)
 
And you are spot on about RAID5.

it is a pretty bad idea to only have one parity drive in an array these days when disks are so large. You are pretty much guaranteed to have data corruption a few times when resilvering your array after a disk failure.
 
thanks for the replies, had a busy couple of days so not had the time to read them until now.

Unfortunately I live in the UK, so some of those parts are either hard to find or somewhat more expensive. I wish the UK had a Newegg equivalent or they did cheap international shipping. But my main goal is to reuse my existing hardware. ECC really is off the cards until my hardware dies or becomes unusable. So I might steer clear of ZFS since I miss a lot of the requirements (no ECC, only 4GB, AMD Hardware, etc).

Just read up a little on snapRAID and it looks interesting. It gives me some basic redundancy, i can run it on Windows 7 and get rid of Windows Server 2008, and most importantly, I can reuse my existing hardware.

If there's other options or some snapRAID reading material I should check out, I'd greatly appreciate the advice!
 
akira181 said:
If there's other options or some snapRAID reading material I should check out, I'd greatly appreciate the advice!
Click to expand...


It's been a few years since I researched alternatives, but I do recall finding a option named "FlexRAID" interesting. A few years ago, I played with it, and determined it wasn't quite ready for me yet, and went with FreeNAS instead, but since then things may have changed.

As I recall it was cross platform (would run on either Windows or Linux) and could provide a userspace RAID like data-rendundancy at low cost. it was open source back then, but I vaguely recall it going commercial.

Maybe google it and see what you can find?
 
Yeah, flexRAID has gone commercial unfortunately.

snapRAID seems to have much less up to date information compared to the other options out there like unRAID, FlexRAID, and FreeNAS but from what I can find, it seems like it's a pretty good system.

Only negative I can see is that parity files are snapshot and not realtime but that's not an issue for me since it's mainly static data. Lose 2 drives and I would only lose data on the dead drives and not the whole array/pool.

I wonder what I'm missing here
 
Only negative I can see is that parity files are snapshot and not realtime but that's not an issue for me since it's mainly static data
Click to expand...

For me that is a positive for mostly static data. It allows for undeletes and also the parity disks only need to be powered on during the sync / scrub ...
 
akira181 said:
I was worried that 4GB RAM might be a touch low, DDR2 RAM is so expensive, it's like the price never dropped since release. Might run FreeNAS for a while and see if I'm happy with the performance before spending cash on another 4GB (would love to have 16GB, but budget comes into it again).
Click to expand...

You know the minimum requirements for any of the recent versions of FreeNas is 8GB right?
 
kenned3 said:
You know the minimum requirements for any of the recent versions of FreeNas is 8GB right?
Click to expand...

yes I know, but there's been stable builds with only 4gb, just performance takes a hit. ECC is the bigger issue with the RAM anyhow.

Later on in the thread, you can see I've swayed away from FreeNAS and leaning towards snapRAID until I am forced to update my hardware.

Just trying to read up more on snapRAID now. Seems like outside of performance (as the data is not striped across multiple disks) and the snapshot backup (which I prefer), it is the best option for me.
 
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