Help changing zfs layout!

[Naesstrom]

So when I first started using freenas my plan was to use it firstly as a backup of my digital photos so I chose the mirrored layout of my drives to get the most secure storage... now as Google is providing me infinite storage of my photos it's mostly media and I feel that the redundancy is a bit overkill tbh. This is my current layout:

With the mirrors as follows:

So... I'm thinking of buying a new 10TB drive, creating a new volume with that one, moving all the stuff from my current volume there and then expanding the new one with the old disks...

Is that possible and what's the best practice, and what kind of layouts should I choose?

 

[danb35]

Is that possible

Of course. Do you want any redundancy at all? Or just a single striped pool?

 

[Jailer]

If you expand that 10TB drive with a new vdev you will have a single point of failure.

 

[Naesstrom]

Of course. Do you want any redundancy at all? Or just a single striped pool?

Some redundance would be nice but at the same time getting more then 50% of the storage would be nice :D

If you expand that 10TB drive with a new vdev you will have a single point of failure.

you mean while moving all the data there... yeah I know but not sure how to make the change otherwise...

 

[Jailer]

you mean while moving all the data there

Not just moving the data there, you said you wanted to expand the drive. Are you planning on leaving the 10TB drive in the server or creating a new pool and moving the data back to the new pool?

 

[Jailer]

And your pool is 99% full, that's a bad thing. You're at risk of data loss if you keep adding data to that pool. Don't fill it past 90% at the absolute maximum preferably 80% as that's the point that performance tanks.

 

[Naesstrom]

Not just moving the data there, you said you wanted to expand the drive. Are you planning on leaving the 10TB drive in the server or creating a new pool and moving the data back to the new pool?

hehe, that's why I asked for best practices doing the transfer! Right now I'm guessing I'll have to do temp volume (stripe) with the 10Gb --> move everything there --> create a new volume from the old disks --> move everything back --> include the 10Gb in that volume. I'm guessing a Raidz1 should be enough...

Right now there's a mix of different sizes:

lets say I create a raidz1 or raidz2 from those and a new 10Gb disk... is it then possible in the future to slowly replace the smaller disks 1 by 1 to a larger capacity?

 

[gpsguy]

I'd do RAIDz2 with your 6 x 4-6TB drives and consider keeping the 10GB in a separate pool for backups, etc.

 

[Naesstrom]

I'd do RAIDz2 with your 6 x 4-6TB drives and consider keeping the 10GB in a separate pool for backups, etc.

you mean the 4x4 and 2x6, so it is possible to mix sizes atleast :D

 

[gpsguy]

Yes, I meant putting all of them in the same RAIDz2 pool. FreeNAS will treat the 6TB drives like 4TB. If you can replace the 4TB drives with 6TB drives (one by one and resilvering), the pool would automatically expand when all the disks have been upgraded.

The volume manager will complain if you try to mix drive sizes in the same vdev. But, if you select the "Manual setup" button in the lower right hand corner of the screen, it will allow you to create a pool like this.

you mean the 4x4 and 2x6, so it is possible to mix sizes atleast

 

[Jailer]

Yes, I meant putting all of them in the same RAIDz2 pool

But that will give him the same usable space that he currently has and his pool is 99% full. That's a bad course of action.

What you really need to do is build a new pool with larger drives or add a new mirror to your existing pool to grow it's capacity.

 

[Arwen]

But that will give him the same usable space that he currently has and his pool is 99% full. That's a bad course of action.
...

Actually not, (and correct me if I am wrong). For RAID-Z2;

6TB+4TB+4TB=14TB, (we only get the space of 1/2 of the Mirrors)
4 disks * 4TB=16TB, (we get only 4 usable drives from the original 6, and only at 4TB)

For RAID-Z1 it's even better;

5 disks * 4TB=20TB, (we get only 5 usable drives from the original 6, and only at 4TB)

In the case of RAID-Z2, we loose 4TB from the 2 x 6TB disks. At least until all the 4TB disks are replaced with something larger.

 

[Jailer]

Now you know why I'm a prison guard and not a mathematician............

 

[gpsguy]

Thanks Arwen - you read my mind. That's exactly what I was thinking.

6TB+4TB+4TB=14TB, (we only get the space of 1/2 of the Mirrors)
4 disks * 4TB=16TB, (we get only 4 usable drives from the original 6, and only at 4TB)

 

[Naesstrom]

*sigh* now I remember why I gave up this idea earlier :D
Thanks for all the help with explaining how they work... Now I'm thinking of buying 2x6TB instead of the 10TB so I can use them in the volume later on instead. I just hate having multiple volumes but maybe that's the best way to go!