FreeNas for Home 2 x 4TB Disks Backup Solution?

[SpiritFly]

Hi all,

So basically what I need is a home nas for basic stuff. Backing up my personal photo collections, videos and working files. I would probably leave it running for torrents uploads/downloads and probably an

I've been doing a lot of reading until I decide whether I should go with Mirror Raid solution or FreeNas. From what I understand everyone is saying that Freenas is the better and safer solution for backups, but what I would like to know is: how do I setup the 2 x 4TB with Freenas? Will they function the same way as mirror raid? One drive for the data and the other one duplicating? Or does it work differently than that concept? Because if the second drive is not mirroring I can't see how can I save my data in case of drive failure in the NAS? Please explain a bit better to me or referrer to some guides on how to setup a 2 bay nas.

And more importantly I'm still thinking about the hardware. There is a FreeNas diskless solution for about 1000$ that I'm considering. There is also a M2N-MX mb that I have laying around and can be transformed. I will just need to buy more ram if I really need that ZFS filesystem. I've read a lot about it, but still don't quite understand if it is really needed in my case with two disks.

 

[danb35]

You can set up two disks in any configuration you like: striped, mirrored, two separate volumes, whatever. If you want redundancy, of course, you'll want to mirror them. You could later add a second (or third, fourth, however many you choose) pair of drives, which would increase the capacity of your pool. See http://forums.freenas.org/index.php...ning-vdev-zpool-zil-and-l2arc-for-noobs.7775/ for quite a bit more information about the basics of ZFS.

The FreeNAS Mini seems pretty well-regarded, and I've heard very good things about iXSystems' support. If that isn't the $1k diskless FreeNAS solution you were looking at, it probably should be. The only drawback is that it only has four drive bays, which may or may not be a concern for you. Unless the M2N-MX supports ECC memory (which it doesn't look like it does), I wouldn't recommend it for a FreeNAS system.

 

[L]

This one is pretty sweet too.

View: http://www.amazon.com/FreeNAS-Mini-Network-Attached-Storage/dp/B00EQJ3PS0/ref=sr_1_5?ie=UTF8&qid=1405351767&sr=8-5&keywords=freenas+mini


It you want mirrored, just select mirrored in setup. I did this video about a year ago, it's focused on using freenas for time machine, but it would work the same except use a cifs share.

View: https://www.youtube.com/watch?v=s2pyYeANGKc

 

[SpiritFly]

Thanks a lot for your help guys! Yes it was the FreeNAS Mini I was referring to when I said $1k Nas system. It suits my needs perfectly well with the 4 bays, but unfortunately it will get pretty expensive to deliver it to where I live so I decided to go for a tower server.

So what I needed to understand is the way ZFS manages mirroring. It seems to me that ZFS can do mirroring without the need of any RAID controller. ZFS Mirror is hardware independant so to speak, except the large ECC ram quantities.. Am I correct?

 

[danb35]

That's correct, no hardware RAID controller is necessary with FreeNAS using ZFS. In fact, hardware RAID controllers are strongly discouraged.

 

[SpiritFly]

So I'm just reading the PowerPoint guide provided, and although I'm an experienced windows user and have a lot of experience with hardware and PCs in general, I must confess I don't quite understand a lot of stuff. I will have to do a lot more research.

What I don't quite understand is this line in the guide:

¨You can think of it simply as:
- Hard drive(s) goes inside VDevs.
- Vdevs go inside zpools.
- Zpools store your data.
- Disk failure isn’t the concern with ZFS. Vdev failure is! Keep the VDevs healthy and your data is safe."
​

By reading through the forums I don't see many setups in mirror mode and it seems to me not much attention is given to it. Does that mean mirroring setup is not required for safety of data when using FreeNAS and ZFS ? If yes, how exactly is the data saved in the case of a Hard Disk failure with ZFS+FreeNAS ?

 

[danb35]

ZFS does a lot of things differently from most other filesystems. In an attempt to make things simpler for users, FreeNAS largely hides the vdev layer, which I think can cause some confusion. As cyberjock's guide says, it is failure of a vdev that will lose data, not (as such) failure of a disk. Whether failure of a disk will cause failure of a vdev (and thus, of a zpool) depends on the configuration and status of the vdev.

If you have a two-disk mirror, those two disks comprise one vdev, and that one vdev comprises your zpool. If a single disk fails, you don't lose any data, because you have a complete copy on the second disk. Therefore, the vdev does not fail, and therefore, your zpool remains intact. Replace the failed disk as soon as possible to restore redundancy to your pool.

Let's suppose that you fill up your ~ 4 TB of capacity, and you want to expand the capacity of your pool. You buy another 4 TB disk and add it to your existing pool, and presto, another 4 TB of capacity. This is what is technically called hating your data, and is a very bad idea. Here's why: when you added the third disk, it was added to a new vdev. When multiple vdevs are present in a zpool, your data is striped across all the vdevs, similar to a RAID 0 arrangement. If any single vdev fails, the entire pool fails--and if your new disk fails, its vdev will also fail, because there is no redundancy for that data.

 

[SpiritFly]

Reading along the presentation and now your answer I think I'm beginning to understand how it works and it will only be a matter of what's best practice to setup my 2 x 4TB when I setup my FreeNAS.

So if I have 2 x 4TB and I later decide to expand capacity, do I buy another set of 2 x 4TB and add them as a second vdev? As I understand I cannot expand the existing vdev of 2x4TB with another set of 4TB can I?

And an honest a little offtopic question: If I were to use my 2 x 4TB for basic purposes like home use and basic file storage without any extensive read/write to the NAS without the need to expand storage in the following 5-6 years, is it really worth it buying a server, installing FreeNAS and all the steep learning as compared to a ready-made NAS server (synology asustor etc..) ? I mean what would be the advantages of using FreeNAS instead of those? Are those read-made servers that bad and unsafe for storing data even with 2 x 4TB ?

EDIT: No need to answer any of it mate. I think I discovered my answers. I can expand by buying disks with larger capacity and replace one by one. And I think I found that FreeNAS can do the things I need easily nowdays with plugins like: torrenting, Apache/MySQL and without jailing so I think it is pretty much decided. I'm going for FreeNAS now. THANKS for all your help! I think I'm going to hang around with you guys around this forum now more, cheers! :)

 

[danb35]

Yes, if you decide to expand your storage in the future, one good way to do it would to be to add another mirrored pair of disks. Another good way would be to add more disks in a RAIDZ configuration. Which would be better would depend on the specifics of your use case, but either way you'd be maintaining data redundancy.

As I see it, the biggest benefit of FreeNAS compared to any pre-made solution is ZFS. When properly implemented, ZFS is simply head and shoulders above pretty much any other filesystem out there in terms of both features and data integrity. That reliability, however, comes with a price. It calls for lots of RAM and a bit of CPU grunt (at least more so than other filesystems). Also, because of its feature-rich nature, ZFS is a bit more complex and has more traps for young players than most other filesystems.

 

[L]

The other really really cool part about zfs is when you go to grow your storage you just add more. No outage, a couple clicks and you just have more. Most of the nas/san boxes need some sort of outage. You might need outage based on the type of storage you add..but the filesystem just goobles it up.

 

[gpsguy]

Another nice thing, is that should your hardware fail, you can move the disks to another computer, assuming you have sufficient RAM. No worries about hardware RAID controllers.

Many years ago, I had a RAID controller fail in a Compaq server. Although I had 24x7 support from Compaq, they didn't have this controller in their warehouses and they didn't know when they'd get one. I had to pay big bucks to source another one.




Sent from my phone

 

[SpiritFly]

Allright FreeNAS wins then :) I'm ordering my HP proliant ML310e Gen8 v2 tomorrow and I'm gonna put those two 4TB in there. I searched around to see if hp proliant ML310e Gen8 v2 will get along fine with FreeNAS, but couldn't find anyone using it except a few threads mentioning the older hp proliant ML310e Gen7 which it seems worked fine for those guys so I'm guessing there's no reason why this Gen8 v2 wouldn't work with FreeNAS.

I will report here how that goes. Thank you for all your answers, you were extremely quick and helpful! Cheers!

 

[Whattteva]

The other really really cool part about zfs is when you go to grow your storage you just add more. No outage, a couple clicks and you just have more. Most of the nas/san boxes need some sort of outage. You might need outage based on the type of storage you add..but the filesystem just goobles it up.

The caveat to that is that you can't grow it dynamically. You either make a second pool and replicate your existing pool there; or you replace your disks, which wouldn't grow your pool until all disks have been replaced.

 

[danb35]

...or add another pair (or more) of disks to your existing pool as a new vdev, which will expand it immediately. You could even add a single disk, but that goes back to the "hating your data" issue.

 

[Whattteva]

...or add another pair (or more) of disks to your existing pool as a new vdev, which will expand it immediately. You could even add a single disk, but that goes back to the "hating your data" issue.

Yeah, but that restricts you to adding 2 or more disks at a time if you want to retain redundancy. Definitely not as convenient as simply just adding another disk to an existing vdev.

 

[danb35]

True. If you want to do that, you'll need a Drobo instead--and say goodbye to ZFS. It looks like btrfs supports this, but it also looks like btrfs isn't ready for prime time yet.

 

[SpiritFly]

So let's take a practical example. In my case I start with 2 x 4TB in one vdev. After a few years I decide to buy one more pair of 4TB. I understand that the new pair of 4TBs cannot be added to the existing vdev so I install the new 2 x 4TB and create a new vdev in the existing pool in order to extend the zpool am I right?

In that case what would be the difference with having the all 4 4TBs right now and adding them all at once as single vdev in one zpool as opposed to having 2 vdevs with 2x4TB ?

 

[danb35]

So let's take a practical example. In my case I start with 2 x 4TB in one vdev. After a few years I decide to buy one more pair of 4TB. I understand that the new pair of 4TBs cannot be added to the existing vdev so I install the new 2 x 4TB and create a new vdev in the existing pool in order to extend the zpool am I right?

Correct. This would allow one disk in each mirror to fail without data loss, but if both disks in a single mirror failed, you'd lose all your data.

In that case what would be the difference with having the all 4 4TBs right now and adding them all at once as single vdev in one zpool as opposed to having 2 vdevs with 2x4TB ?

If you have all four disks now, you have more options in how to set them up. You could set them up as two mirrored pairs, which would give you exactly the same result as what you describe above. You could set them up in a RAIDZ1 pool, which would give you greater capacity (~ 12 TB), but less redundancy. Or you could set them up in a RAIDZ2 pool, which would give you the same capacity (~ 8 TB), but different redundancy--RAIDZ2 would tolerate the failure of any two disks without data loss, compared to only one in each mirror with mirrored pairs.

 

[SpiritFly]

Correct. This would allow one disk in each mirror to fail without data loss, but if both disks in a single mirror failed, you'd lose all your data.

If you have all four disks now, you have more options in how to set them up. You could set them up as two mirrored pairs, which would give you exactly the same result as what you describe above. You could set them up in a RAIDZ1 pool, which would give you greater capacity (~ 12 TB), but less redundancy. Or you could set them up in a RAIDZ2 pool, which would give you the same capacity (~ 8 TB), but different redundancy--RAIDZ2 would tolerate the failure of any two disks without data loss, compared to only one in each mirror with mirrored pairs.

This is what worries me. At this point I'm good with 4TBs, but I may buy 2 more 4TBs in future and would prefer the RAIDZ2 setup which tolerates failure of any two disks. Sadly I won't be able to do that afterwards.. But if I buy 4 x 4TBs now and only use 4 TB space max for a few years to come, then what's the use of having two more just laying there. Not sure what to do now. I guess I'll have to live with two mirror pairs..

 

[Whattteva]

Yeah, this is the reason why I waited until I had all the parts I needed and did it all in one go. It's a far more robust set up and I don't have to worry about it for a long long long time.