I have a few questions about unraid

[xamindar]

I have been reading about this the last couple of days and am trying to figure out if this is what I want. What I am looking for is some way to turn my old hardware into something like what that drobo does. Basically:

1)allow 3 or more drives to be lumped into one large drive so all I have to do is copy things over to it and stuff ends up on whatever drive has space. At the moment I am using LVM in linux (same as JBoD) to do this and it works fine. But if a drive fails everything is gone.

2)Next thing I need is some sort of redundancy which LVM does not provide. I can't use normal raid because it requires all drives to be the same size and they aren't. Hopefully something that provides redundancy without loosing too much space.

3)Ability to add larger drives as they become available and remove smaller ones later on so I can increase available space without starting over each time. Something I really liked when reading about that drobo.

 

Does unraid allow all this? Does it allow me to have a bunch of different sized disks show as one disk and have redundancy for at least a single drive failure?

 

I saw something else out there called flexraid but when reading about it it looks like all the drives come up as something like:

/drive1

/drive2

/drive3

/parity

and then you just have to put things in the drive that has space available. Unless I read that wrong. But that is not what I want at all.

 

One drawback I see with unraid is that it has to run from a usb drive. Doesn't that limit a lot of what you can do with it? It's basically a NAS drive?

Is there any way to run unraid from an internal drive on the linux distro of my choice and maybe have the usb flash disk inserted so the licence is valid or whatever it needs it for?

 

The machine I hope to run this on (or any sollution that will allow me a raid type expandable drive) does not boot from usb so this is the point I'm a little stuck on.

Thanks for any help.

 

[purko]

I have been reading about this the last couple of days and am trying to figure out if this is what I want. What I am looking for is some way to turn my old hardware into something like what that drobo does. Basically:

1)allow 3 or more drives to be lumped into one large drive so all I have to do is copy things over to it and stuff ends up on whatever drive has space. At the moment I am using LVM in linux (same as JBoD) to do this and it works fine. But if a drive fails everything is gone.

2)Next thing I need is some sort of redundancy which LVM does not provide. I can't use normal raid because it requires all drives to be the same size and they aren't. Hopefully something that provides redundancy without loosing too much space.

3)Ability to add larger drives as they become available and remove smaller ones later on so I can increase available space without starting over each time. Something I really liked when reading about that drobo.

 

Does unraid allow all this?

Yes.

 

Does it allow me to have a bunch of different sized disks show as one disk and have redundancy for at least a single drive failure?

Yes.

 

I saw something else out there called flexraid

Flexraid is crap.

 

One drawback I see with unraid is that it has to run from a usb drive.

It doesn't run from a usb drive.  It boots from a usb drive.  It runs from ram.

 

Doesn't that limit a lot of what you can do with it?

What is it that you want to do with it?

 

 

[purko]

The machine I hope to run this on (or any sollution that will allow me a raid type expandable drive) does not boot from usb so this is the point I'm a little stuck on.

 

You can make unRAID boot from CD, or you can boot using a "kicker" floppy.  See this:

http://lime-technology.com/wiki/index.php?title=Best_of_the_Forums#USB_Boot_Issues

 

 

[bubbaQ]

And you can install it to the hard drive and boot from there (as long as the USB stick is still plugged in to get the license file and superblock).

[xamindar]

Thanks for the replies. Looks like the best option for me on this computer is to make a bootable cd image. That link to USB boot issues looked really good until I tried it. But when I clicked on "Create Bootable isolinux CD to replace flash" it just took me to a forum post with one single post from someone who said they created a bootable cd and it worked. Things must have changed because the way he said he did it doesn't work. mkisofs requires files that don't exist and there is no explanation of how to create them. I might have to drag a floppy drive out of the closet and hope I still have a floppy cable somewhere. I'm surprised at the lack of documentation on unraid. The wiki looks promising until you start clicking on the links, very vague instructions and often just links to a forum post someone made two years ago. Again, thanks for the tips, I'm pretty frustrated with this thing at the moment. I'll do some more searching for a solution.

[WeeboTech]

Is there any way to run unraid from an internal drive on the linux distro of my choice and maybe have the usb flash disk inserted so the licence is valid or whatever it needs it for?

 

Yes, it has been done, search the board for running unRAID on a full distro.

Many of us still use the boot flash to initramfs method, then install thirdparty add on packages after booting.

[xamindar]

Alright, I got it working. I stuck a very small (4 gig) ide hard drive I had into a usb enclosure and installed unraid just like you would on any other usb drive. Then stuck it back into that computer and also plugged in the usb stick and it booted up perfectly. I'll mess around with this free version and see how I like it. So far so good.

 

I do have a question about the parity drive. It does have to be the largest one right? What happens if I add an even larger drive to the array in the future? Will it move parity over to the correct one, will it even need to? Will I need to do anything special? Thanks for the help.

[prostuff1]

The wiki looks promising until you start clicking on the links, very vague instructions and often just links to a forum post someone made two years ago.

As someone who has spent a lot of time messing with the wiki and trying to better organize it I take a little offense to this statement.  I know you probably did not mean it that way but still...

Anyway, if you think the wiki needs improving then feel free to do so yourself or give some feedback and if/when someone can get to it we will.  Some/most of those forum post that are linked are still very valid today.  It is/was done that way so that if changes were needed they could be made to the thread in the forum and not to the wiki entry.  The wiki is just a "repository" of links to whatever you would like.

 

Again, thanks for the tips, I'm pretty frustrated with this thing at the moment.

That will pass, I promise.  Once upon a time I was the same way but now that I have unRAID up and running I could not be happier.

 

Alright, I got it working. I stuck a very small (4 gig) ide hard drive I had into a usb enclosure and installed unraid just like you would on any other usb drive. Then stuck it back into that computer and also plugged in the usb stick and it booted up perfectly. I'll mess around with this free version and see how I like it. So far so good.

Why do you want to run it off a hard drive?  This really just adds a step that is not needed.  Do a search in the unRAID wiki for Plop Boot Manager.  It should allow you to "boot" from the USB thumb drive even though your motherboard does not support it.  Also check of the Third Party Boot Flash Plugin Architecture section for an idea of how some unRAID users install third party apps on there server.  The Customization Forum has detailed instructions on how to install a lot of third party software and if you read through a couple of those you will get and idea in a matter of no time how everything ties together.

 

I do have a question about the parity drive. It does have to be the largest one right? What happens if I add an even larger drive to the array in the future? Will it move parity over to the correct one, will it even need to? Will I need to do anything special? Thanks for the help.

Yes, it does have to be the largest. There are a couple ways to go about it but the way I do it is:

1. Unassign old parity drive

2. Assign new and larger drive to parity

3. Leave old parity out of the array for now

4. Build parity onto the new drive

5. Check parity to make sure everything is good

6. Let the array alone for a couple weeks or more to make sure everything keeps running properly

7. Run preclear on the old parity drive

8. Assign old parity to the array

[xamindar]

Sorry prostuff1, I take back what I said about the wiki. With the exception of my complaints above everything else I have wondered about I was able to find in the wiki and it has helped a lot in understanding the way unraid works. My complaints above are about things that are not officially supported by unraid anyway.

 

I set up my test machine with three drives and have been copying stuff over to them. I found it strange at first how it lists each drive as a seperate share but I guess it makes sense because the data is not striped across disks. On that note, if I had a disk that only has say 5 gigs free and attempted to copy a 10gig file to it, instead of it pooling over to a disk that had more space I would get a disk full error right? But then with a user share it would automatically put that file on another disk that had space?

 

I tried testing a failure by pulling a drive and am happy to find that the data on the pulled drive is still available. Now, after putting the drive back in the web interface states "Stopped. Disabled disk replaced." (I powered down to pull the disk) Now it gets really confusing, I'm not sure to press Start or Restore. Without reading the caption next to the buttons I would assume to press restore as in to restore the array and incorporate the new disk. And that pressing start will just start an unprotected array without the new drive.

Now reading the caption next to start it says "Start will bring the array on-line, start Data-Rebuild, and then expand the file system (if possible)." Ok, so what I really need to press is the start button because I want to bring it online, expand to the new drive, and rebuild the data on it.

But when I read the caption next to restore "Restore will initialize the stored array configuration; all drives will appear as New, but data disk contents are not affected." What in the world does this mean? All drives will appear as new? It sounds like it will erase everything. Then it says data disk contents are not affected, but didn't it just say all will be as new? And what about the parity drive? It says nothing about that. It seems to contradict or at least not explain what it means in clear enough english. (Did a lawyer write this?) I do want to "initialize the stored array configuration" so now I have no idea what to press.

 

Can anyone help me out here? Why is it worded so confusing?

So far I am loving this and will be buying it when I build a proper unraid box (ordered a case and mini-itx board today

 

Oh, one more question. When I move the drives and the unraid flash stick over to the new motherboard will unraid be able to start the array as if nothing happened? Or will it want to erase everything and set it up from scratch?

[Joe L.]

The button labeled as "restore" does Not restore data. It is actually a "Set Disk Configuration" button.  It immediately sets a new disk configuration based on the existing assigned and working disk and immediately invalidates parity.  If you were to press it in your situation it would throw away the data you were trying to rebuild onto the replacement drive.

 

The correct button to press is "Start"

 

The "restore" term is apparently one the developer uses in terms of restoring the array to a state before parity has been calculated.  It is VERY misleading.  If you were to press it after replacing a failed disk you would lose the data on that disk.

 

It is needed at times... specifically when you are making hardware changes to the array and using new disk controller ports.  Also, it is needed if you are removing  a disk permanently from the array and not putting a replacement in the same slot in the array.  (Un-assigning a disk is not enough, as un-assigning a disk is exactly the same as a failed disk.  its contents will be simulated.

[xamindar]

Thanks Joe. So if I understand correctly, hitting restore will keep data on any existing disks that were not touched but any that were changed will be dumped and formatted as a new, empty disk. And it will dump parity and have to recalculate that from scratch. So it just gathers the disks that still have valid data and starts a new parity calculation for them?

 

For example, I move all the disks to a new motherboard and in turn they end up on different ports. In this case, simply clicking restore would cause it to find them all and set up the array again? I hope I have it right now. Thanks for the clarification.

[Joe L.]

For example, I move all the disks to a new motherboard and in turn they end up on different ports. In this case, simply clicking restore would cause it to find them all and set up the array again? I hope I have it right now. Thanks for the clarification.

As long as you did not assign a data disk to the parity slot on the array it would work.  If you ever move disks, make sure the parity disk is assigned to the parity slot in the array before pressing "restore."

 

If you got it wrong, the data disk you accidentally assign as parity would be overwritten with parity calculations, destroying any data in it, and the parity disk would be found to not have a file-system on it and it would show as "unformatted"

 

Best bet... when you get all your disks assigned, get a screen-print of the "devices" page for future reference.

 

Joe L.