First NAS and a bunch of questions/considerations

[_X_]

Hi guys,

I'm new to the FreeNAS world and I would like some advice in terms of ZFS concepts from the pro's among us. I went through the FreeNAS 4 Noobs documentation in this forum and I've been reading up on RAIDZ 'levels' and similar 'What setup is best for me?', but I've gotten clueless on what would work for me.

My setup is the following:

5 x 4Tb HDD
1 x 3Tb HDD
FreeNAS runs on a USB dongle

I would like to use this NAS for two things mainly:
*Serve up my media library across the home network
*Archive: Storing backups (A NAS isn't a backup solution I know ), documents and files I would like to keep, ...

From what I have been reading, the right RAIDZ setup would depends on the following trade-offs:
*Read/Write Performance
*Data stability (disk failure)/Storage capacity

Did I get this right?
If yes, I would want my media library to have a good read performance (it's written once, read more frequently) and storage capacity would be more important than stability.

However the 'Archive' is the exact opposite, keep the data is important over storage.

Can anyone let me know if my reasoning is sound? Am I missing something? What setup would you recommend for this?

Thanks a bunch

 

[gpsguy]

Buy another 4Tb drive and put 6 of them in RAiDz2. This is a good balance for your use case. Having RAIDz2 gives you extra protection if you have to replace a drive in the future.


Sent from my phone

 

[_X_]

Thanks for the advice. I'll look into it. Some questions though:
*Putting them all on RAIDZ2, do you mean 1 zpool -> 1 vdev?
*Is there no alternative with the 3Tb? Might take a while to get that 4Tb

 

[jgreco]

Yeah you should be able to make a RAIDZ2 vdev out of the drives as-is, but they'll be limited to the size of the smallest component (3TB). That gives you 12TB today and 16TB when you upgrade the 3TB to 4TB.

 

[_X_]

Thanks for your reply. That's a good thing. 12 TB should be enough for now, I'll try to have the 4 TB next month. Does it impact performance to have one 3TB?
Would it be sensible to divide it in two vols? One for media and another for the archive? That way I can have encryption on the archive vol and leave the media vol without encryption.
Not sure if that's the way to go...

 

[joelmusicman]

No negative impact, you're just not seeing the benefit of the 4tb drives. Roll with that config for now and upgrade once you use about 8TB or so. There's really no need to rush unless you need 16TB. Definitely run RAIDZ2 though.

Volumes: That's sensible. Note that transferring files between volumes is pretty slow though as the drives are literally reading and writing back to themselves. I have all my files on one volume for easier organization. Personally I'm more worried about not being able to decrypt my own stuff than someone else hacking it.

Definitely keep your pool below 90% utilization at all times though.

 

[_X_]

I'll go for one volume for now. As for encryption, I'll read up on it on the FreeNAS documentation before considering using it.
I've tried making one volume from 5 4Tbs on RAIDZ2, and I get "non-optimal" as you can see. Most likely because it puts the 5 4TB disks in
a vdev (not sure...) and stores the 3TB disk on a separated one. In the doc it says 6 disks are the optimal config for RAIDZ2.

Is there a way to squeeze in the 3TB in the RAIDZ2 as well? Apologies for my n00b questions that you have to cope with.

 

[cyberjock]

Yes. Click that "manual setup" button and put them all in there. It will shrink your pool temporarily, but you'll get the disk space back when you replace the 3TB drive.

 

[joelmusicman]

Wow. I'm amazed that the GUI would even suggest such a retarded configuration!

 

[cyberjock]

It didn't exactly offer it. It initially offered the 5 disk pool. Then the user probably "added" the 3TB, and it did it as a separate stripe because you've made selections that are already non-optimal.

The volume manager basically does a bunch of things, and as soon as you start deviating from its recommended configuration, then everything falls apart.

 

[_X_]

Thanks for pointing out the 'Manual setup' button...I didn't really see it. One last thing: Would I want deduplication in my case? I've been reading up on the value of deduplication and the answer doesn't seem
to be clear in my case.

 

[gpsguy]

Don't do de-dupe. The thumb rule is 5Gb RAM for 1Tb space with no upper bound.


Sent from my phone

 

[jgreco]

The other rule of thumb is if you have to ask if dedupe is for you, the answer is eff, no!!

 

[_X_]

haha, gotcha, jgreco. Added dedupe to my todo list of zfs schooling. I must say, it's an exciting feeling to setup your first zpool, similar to the first meters you would do on a bike without the training wheels ;). However, I only have 10.7 TiB instead of 12 TB. Did I do something wrong? I also went for lz4 compression as it was recommended.

I've been playing with the concepts of ZFS Datasets and zvols and folders.

It became clear that Datasets are more flexible than zVols and they allow you to define permissions on them, which makes me think that Datasets are more useful in my scenario. What I fail to see, is the use for vdevs and how they would fit in my world. The biggest concern I have, is I don't have a clue where to draw the line in using Datasets or plain folders and if it is the right way to go. What's are the key differences between a Dataset and a folder?

I tried finding more to read on the difference and best practice, but alas. I've played with both and I was able to note that there are some behavioral differences in using ZFS Datasets and directories (example: When creating a CIFS share, it does show you the child Datasets on a mapped drive, not the case with folders. Think it may be a permission inheritance issue).

Having said that, here's how I would like to proceed:

Have one zpool for the 6 disks on RAIDZ2
*Dataset -> Media with the following folders:
Audio
Video
Photos
*Dataset -> Archive with the following folders
Backup

Would this be the way to go or should I go for nested datasets?
Thanks a lot for your input, guys. I really appreciate it

 

[enemy85]

You have 10,7TiB instead of 12TB because freenas works with TiB and that is the exact conversion...