Dataset expansion after Expanding Volume

[ZombieHorde]

As you can see, I've increased the the size of my RaidZ pool by replacing the four 1.5 tb drives to 3tb drives. The pool picked it up, the datasets on the pool do not. Can anyone explain this apparent conundrum to me or is there anyway to allow the dataset to pick up the extra storage on the drives?

 

[depasseg]

What makes you think it isn't being recognized? The 4.3TiB is free space.

 

[ZombieHorde]

What makes you think it isn't being recognized? The 4.3TiB is free space.

Notice, the Pool says 6.3 tib free the Dataset only shows 4.3 tib free. Shouldn't that be 6.3?

 

[depasseg]

Your pool is 4.3 TiB free. The 6.3 doesn't factor in RAID (IOW it's the raw value). What did your pool report for free space prior to the disk upgrades?

 

[ZombieHorde]

That's nice to know. I thought it took into account the raid as that's what the pool was defining. No, I definitely got some space, just not as much as I would have thought considering I went from 4.5 tb raidz1 to (i.e. 4 1.5 tb drives) to 9 tb raidz1 (3 tb drives). I know it's bad to have Raidz1 over 3tb drives, but I already had the array built and I need the additional disk space. i.e. a media server with lots of movies. So, to clarify, pools only show raw disk space, not striped disk space available?

 

[depasseg]

So, to clarify, pools only show raw disk space, not striped disk space available?

I'm not sure where striped disks came from?
Pools are what they are. However, it's the FreeNAS GUI which shows both raw and usable. The first line in your screenshot is raw and the second line is usable. They both describe the pool. If ever you are in doubt, run zfs list from the cli (or SSH). It will give you the usable space.

 

[ZombieHorde]

Striped came from the Raidz1 setup I have the drives in. From my understanding of ZFS nomenclature, that is the sorta kinda equivalent of a standard Raid5 setup with striped set using up basically one drive equivalent for striping. The ZFS naming for things kinda confuses the issue, so that's based on my basic understanding from reading the ZFS documentation on the FreeNAS sight as well as Oracle's documentation on ZFS. It's fascinating and confusing to some extent at the same time.

 

[ZombieHorde]

Digging around, I'm curious. Normal rule of thumb is one drive equivalent of space is chewed up in a Raid5 standard configuration. So, for example, 4 1tb drives in Raid 5 results in around 3 tb of usable space, less after formatting. How does that work with the RaidZ1 configuration? About how much would be usable space in that kind of configuration?

 

[BigDave]

@Bidule0hm has a good post here that links to his awesome RAIDz calculator.
Easy with that shovel mister:p

 

[ZombieHorde]

That was an eye opener. Geez, almost 1/2 the stated disk space. The difference between TB and Tib is really striking. So instead of 12TB I actually got 10.9 Tib. I lost two TB of disk space to Tib conversion. I used to always think of KB/MB/GB/TB being based on 1024, but after reading up on the new more accurate nomenclature, i.e Kib/Mib/Gib/Tib, that the disk manufacturer's have been selling us all a bill of goods based on raw 1000 based ratings instead of the much more accurate 1024 ratings. This is all good information. Thanks, guys.

 

[BigDave]

Yeah, we're all smarter, but now we're pissed off.
Ignorance is bliss :)

 

[ZombieHorde]

Ignorance can be cured, but stupidity is permanent...

 

[Robert Trevellyan]

Striped came from the Raidz1 setup I have the drives in.

In ZFS, striping is what you do when you combine vdevs into a pool. The structure of each vdev determines whether your pool has any redundancy. In the simplest case, each vdev is a single disk, and when striped together there is no redundancy (analogous to RAID0). It sounds like you have a pool made from a single RAIDZ1 vdev, hence "striped" is not applicable.

 

[ZombieHorde]

Well, then. Curing ignorance. That's really good to know.