First NAS - JBOD and expanding pool possible?

[pro_odeh]

Hi,
I decided to build a NAS out of some old hard drives I've had laying around. They are all different sizes; 1TB, 500GB, 320GB. It will be used as local backup (I have a remote backup as well), and access to my files from the net and PS3. I've tried to find out if two features I want are available in FreeNAS, but have not found definite answers, so I'm hoping someone here can help me!

The first feature is that I would like to have all the disks act as one big data pool, utilizing all the disk space. Since the NAS will be one of two backup solutions, it's not critical to have data redundancy, but the ideal if a drive failed would be if only the data on that drive was lost. Is this possible in any form?

The second feature is that I would like to add additional drives to the pool. I have 2x160GB drives that will be added in a couple of months. Is it possible to expand a pool with additional drives without having to format everything?

I'm hoping someone can help me find definite answers to these questions!

 

[pro_odeh]

Thank you for the very helpful answer...
I've been through both the manual and your slideshow, in addition to days of google-ing. The reason I posted the questions was, as I said, to get definite answers.

In FreeNAS 7 a JBOD was an option, in 8 it's not. I could add all the drives as RAIDZ, but in that way I would loose a lot of space. So the closest option I've found is making each drive a single vdev, and adding them to the same pool. But I would still loose all data if one drive fails, so my question was if there are any other options? Judging from your answer I would say no.
And this approach would not take advantage of the ZFS file system, so might I just as well go with UFS? Or perhaps a different solution would be better suited, like Nas4Free?

 

[Stephens]

The first feature is that I would like to have all the disks act as one big data pool, utilizing all the disk space.

I'd look at other solutions. But before you assume it's NAS4Free, I'd make sure to ask the exact same question and make sure you listen closely to the answers. To quote...

JBODs don't provide any redundancy. If one drive fails all data are lost.

Here are some of the things I looked at when I was looking...
- FreeNAS, OpenMediaVauls, NAS4Free, OpenFiler
- uNRAID, FlexRAID

 

[bollar]

I think what you want to do it not FreeNAS 8's strength. I would look at other alternatives, such as NAS4Free, which is the successor to FreeNAS 7.

(sorry to basically repeat Stephens post)

 

[ProtoSD]

Actually, I don't think nas4free will do this any better or worse than FreeNAS. They're both based on FreeBSD, and below the surface the pools are either ZFS or UFS.

I think what you want to do is perfectly reasonable to do with FreeNAS. Sure it doesn't take advantage of ZFS's strengths, but flexibility is one of the advantages of Unix based systems and if you're aware of this risks you're taking, then I don't see a problem.

 

[Stephens]

I always defer to the people who put in a lot of work answering questions here, developing guides/faq's, etc. (mostly because I never have the time to do so myself, so I appreciate that they do all the more), but I really have to ask in this case protosd (because I don't know and can't see it)...

Tell me how he can have any FreeNAS 8.x setup where he has various sized drives using the full space of each drive all in one big pool and if one drive dies, data isn't lost on the others. Because that's his stated criteria in the initial post and I see no obvious scenario outlined in either the FAQ, noobsauce80's guide, or the documentation which would seem to support that.

 

[jgreco]

I think it's because none of us have really bothered to experiment with such configurations.

 

[ProtoSD]

Tell me how he can have any FreeNAS 8.x setup where he has various sized drives using the full space of each drive all in one big pool and if one drive dies, data isn't lost on the others. Because that's his stated criteria in the initial post and I see no obvious scenario outlined in either the FAQ, noobsauce80's guide, or the documentation which would seem to support that.

It's not possible the way he stated it. I was suggesting as an alternative that he could create several pools, one for each disk and add shares for each of the disks.

 

[cyberjock]

Tell me how he can have any FreeNAS 8.x setup where he has various sized drives using the full space of each drive all in one big pool and if one drive dies, data isn't lost on the others. Because that's his stated criteria in the initial post and I see no obvious scenario outlined in either the FAQ, noobsauce80's guide, or the documentation which would seem to support that.

You can't do what is in bold. Read up on the law of conservation of data(i forget the exact name and I couldn't find it with google). Put simply the law of conservation of data states that using parity and checksums it is not possible to recreate missing/corrupt data that exceeds the number of bits that are incorrect. For example, if you have 10 bytes of checksum for any amount of data it is impossible to "repair" more than 10 bytes of data. Compression does seem to "break" this law because you can reconstitute smaller amounts of data back to the original amount. However keep in mind that compression is not the same as parity and checksums. ;)

 

[Strohminator]

For what you're looking for, something like UnRAID or flexraid seems to be a more feasible solution..

 

[pro_odeh]

Thanks for the replies, I feel the issue is clear now. As I said, since this will be one of two backup solutions (i.e. I'll have three copies of my data all together) redundancy is not critical. I could live with the data loss if one drive fails (as I have two other copies), it's more the hassle of setting up a new pool and copying the data all over again I'm thinking about. I've run Windows on RAID0 since 2004, so I'm familiar with the risk.

As of now I'm contemplating two options.

• Going with FreeNAS and hoping disk failures don't happen too often. It's lightweight and almost just what I'm looking for.
• Going with Amahi, which has the exact functionality I was looking for through Grayhole. (I'm reading up on it as we speak)

Do any of you have experience with Amahi, or any input to the options above?
Thanks a lot for the help so far, it's greatly appreciated!

Edit:
I see uNRAID and FlexRAID have been mentioned twice already. It seems they do have the functionality described, but I would like to exhaust all free solutions first.

 

[ProtoSD]

Here are some other options, but I don't know the details:

Openfiler
UnRaid
FlexRAID
Open Media Vault
Drive Extender

 

[pirateghost]

stay far away from openfiler.....there was a time when it was a good product, but the project has become fairly inactive and still remains quite buggy.
it will kind of do what is being asked, because you can use LVM

if i were to go with a different product than freenas, it would be open media vault. i have used it and i do like it, it also allows for LVM configurations

 

[pro_odeh]

Eventually I went with open media vault. Thanks for all the help!