SOLVED Possible to add 5th drive to 4 drives in RAID0?

[Robert Thomspon]

Hey guys... Maybe I went about this the wrong way having assumed some things that aren't as easy as I had originally anticipated...

I have 4 5TB drives that are individual drives by the BIOS, but are run as RAID0 (striped) in FreeNAS... I had been under the assumption that I could add a 5th drive to this set to expand my storage from 20TB to 25TB... But, I am finding this more difficult than I had originally anticipated... Is this actually possible to do (I was informed prior to this that it was, and google seems to agree...)
Or, maybe I have my rig set up incorrectly to do this? (all I did was create the Volume "Storage" from the 4 drives in striped RAID... then began copying from backups onto FreeNAS... did I want to do something in between?

Additionally, I came across another post that said that the virtual drive as I have it set up would be slower than if I had set up a zvol ? Do I want to create a zvol before doing the data dump back to the system?

If I haven't provided enough information, please just let me know what more you need and ill be happy to provide information.... My biggest concern is getting the 5th drive attached for a larger storage pool...

 

[Ericloewe]

http://doc.freenas.org/11/storage.html#volumes

Note the "Volume to extend" list.

Also, I should mention that RAID0 means that reliability will be atrocious, especially with so many drives.

 

[Robert Thomspon]

Right, I've done the "Volume to Extend"... Selected "Storage" (As it's my only volume)... but after running, nothing happens. If I select the added drive, I get error:

• You are trying to add a virtual device consisting of 1 device(s) in a pool that has a virtual device consisting of 4 device(s)
  

Here are screenshots...

 

[danb35]

Yeah, they've added some overzealous warning messages in an attempt to stop people from doing stupid things (usually striping in a single disk with a RAIDZn pool). You'll need to use the Manual Setup button to accomplish this.

 

[Ericloewe]

Right, I've done the "Volume to Extend"... Selected "Storage" (As it's my only volume)... but after running, nothing happens. If I select the added drive, I get error:

• You are trying to add a virtual device consisting of 1 device(s) in a pool that has a virtual device consisting of 4 device(s)

Hmm, that's a bug. There are four vdevs of one drive each (unless you somehow have 20TB HDDs, which I doubt).

https://bugs.freenas.org/issues/25721

 

[Robert Thomspon]

OK... SO!!! Manual setup was the way to go... There is an additional bug... There is a warning that on the extend, all data will be lost (it won't)...

Thanks guys... looks like I could have stumbled through this and figured it out... just a lot of warnings that weren't pertinent...

Screen shot is after the drive was added... sorry, I didn't take a shot before I pulled the trigger... Again, the warning is a false warning... Data remains after attaching the 5th drive...

 

[danb35]

There is a warning that on the extend, all data will be lost (it won't)...

Any data on the disk(s) you're adding will be lost. Data on the pool you're extending is, as you note, unaffected.

 

[Robert Thomspon]

AH! So, the warning is for the disk that is being added, not the disks that already exist... gotcha... makes WAY more sense now.

 

[garm]

Additionally, I came across another post that said that the virtual drive as I have it set up would be slower than if I had set up a zvol ? Do I want to create a zvol before doing the data dump back to the system

Having 25 TB of volatile storage aside.
I would really like to see a reference for this.
Since a zvol would live on your pool..

 

[Robert Thomspon]

Having 25 TB of volatile storage aside.
I would really like to see a reference for this.
Sins a zvol would live on your pool..

https://forums.freenas.org/index.ph...oss-disks-impossible.39023/page-2#post-396488

See post #33

 

[garm]

He never mentions zvol or vdevs. That discussions sounded like it was regarding the use of virtual drives, which is a terrible idea with zfs. But as stated in the thread, it never got explained by the author.

 

[Robert Thomspon]

He never mentions zvol or vdevs. That discussions sounded like it was regarding the use of virtual drives, which is a terrible idea with zfs. But as stated in the thread, it never got explained by the author.

He mentioned virtual disks... which, is in fact, what you create when you create a striped volume in FreeNAS... as is evidenced by:

"You also seem like you are using virtual disks which is also another terrible idea."

I am assuming he is referring to something else... and, frankly, this is now out of the scope of the original post... All of my questions have been answered... thank you.

 

[danb35]

He mentioned virtual disks... which, is in fact, what you create when you create a striped volume in FreeNAS

No, they aren't. A virtual disk is a file on disk that a VM hypervisor uses as though it were a disk. It has nothing to do with a vdev (which is what each disk in a striped volume is, and is also what each RAID set is). You're equating two completely different things.

 

[Robert Thomspon]

No, they aren't. A virtual disk is a file on disk that a VM hypervisor uses as though it were a disk. It has nothing to do with a vdev (which is what each disk in a striped volume is, and is also what each RAID set is). You're equating two completely different things.

OK... not that I really want to debate this endlessly... and again, my questions have been answered... BUT... when you create a RAID0 in FreeNAS, you are not creating 1 physical disk... you are, in essence, creating a virtual volume... a virtual disk as it were that pools several disks into 1 entity that the software treats as a single entity... It wasn't really clear what the poster was referring to and yes, I drew the wrong conclusion as was alluded to above... that doesn't change the fact that when you treat several disks as a single disk, you are creating a virtual disk from the combination...

With that said, I would like to once again say that my questions have been answered, the post has been labeled as solved... could we move on?

 

[danb35]

when you create a RAID0 in FreeNAS, you are not creating 1 physical disk... you are, in essence, creating a virtual volume... a virtual disk as it were that pools several disks into 1 entity that the software treats as a single entity

No, you aren't. You are creating a real volume (not a virtual volume), which consists of multiple virtual devices (vdevs, each disk in this case being a vdev). A virtual disk is something completely different. As it's used in the thread you link to, it means the same thing as I said in my post above, which has nothing whatsoever to do with vdevs, pools, zvols, or anything else ZFS. If you think otherwise, you're confused.

could we move on?

Not as long as you continue to equate different things. You're entitled to your opinions, but you aren't entitled to your own facts. And sure, in a vacuum, "virtual disk" could be used in the way you describe--but it isn't. The way you're describing it is simply not what the term means, and I'm not going to "move on" from an error like that.

 

[Stux]

AH! So, the warning is for the disk that is being added, not the disks that already exist... gotcha... makes WAY more sense now.

@dlavigne OP has a point. The warning implies his pool will be erased...