Help needed: Remove one disk from the array


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Hi everybody,

 

I have a disk (disk3) which seems to be slightly damaged. Nothing serious for now because the array is still healthy but because that's the disk where my docker.img and /appdata folder live, I would prefer to move them to a different disk so I reduce risks and also reduce stress on the worn out disk. I'm trying to use unBalance but it seems it doesn't do it despite it says the operation was successful. I guess it's a permission problem, and if I try to change the user for unBalance from nobody to root, it turns back to nobody. Does anybody has any clue or idea that could help me?

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36 minutes ago, almarma said:

(disk3) which seems to be slightly damaged. Nothing serious for now because the array is still healthy

Parity protection requires ALL disks to be healthy. If you were to have a failure on another disk, you would be relying on your "slightly damaged" disk to rebuild the data from the other disk. This is a recipe for disaster, I have first hand experience with this.

 

You should be concentrating on getting that disk replaced so it's completely out of the parity protected array.

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6 minutes ago, jonathanm said:

You should be concentrating on getting that disk replaced so it's completely out of the parity protected array.

Thanks. I know, but I'm broken an unemployed right now and I cannot afford buying one :(. But I'll do as soon as I can afford it. Meanwhile I need to minimize risks as much as I can so I want to be gentle with that disk and reduce it's usage. But maybe I stress a different one and happens what you say, so maybe it's better to let it as it is now. I'm not sure what to do now :(

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39 minutes ago, almarma said:

Thanks. I know, but I'm broken an unemployed right now and I cannot afford buying one :(. But I'll do as soon as I can afford it. Meanwhile I need to minimize risks as much as I can so I want to be gentle with that disk and reduce it's usage. But maybe I stress a different one and happens what you say, so maybe it's better to let it as it is now. I'm not sure what to do now :(

How much free space do you have on the array? What size are your drives?

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5 minutes ago, jonathanm said:

How much free space do you have on the array? What size are your drives?

I have 5 disks between 3TB and 1TB in size + the parity drive (3TB).

 

The total size of the array is 9.3TB and usage is at 6.75TB (70%) but the disk3 (the one with a few read failures) is at 94% usage ratio

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What exactly is the nature of the "damage"? Go to Tools - Diagnostics and attach the complete diagnostics zip file to your next post.

 

Possibly you could move everything off that disk and just remove it, but before recommending that and explaining how to do so, I would like to see the complete diagnostics.

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3 minutes ago, trurl said:

Disk3 has got to go.

 

Unfortunately, you don't quite have enough remaining capacity on the other disks to hold its contents.

 

Do you have another copy of anything important and irreplaceable?

Thank you. Yes, many of the content are movies which can be re downloaded. There're some backups from my Macs too, and some important stuff too, but it doesn't take that much, so I'll do a big cleanup and remote it.

 

I'm just wondering one thing: is it better for the whole array to remove it or to just use it with irrelevant stuff? I mean, can it affect negatively to the whole array or can it still be useful to reconstruct the array in case of another failure?

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Hi,

 

I have an issue with one of my disks and I want to shut it down. Right now I have a very tight budget and cannot afford to buy a new one. The broken disk is the most crucial one I think because it stores the docker.img and the /appdata/ folder. Let me first describe better the situation:

 

- Parity disk: 3TB

- Disk1: 3TB (used mainly for Time Machine backups)

- Disk2: 1.5TB

- Disk3: THE BROKEN ONE. It holds shares and the docker.img plus the /appdata/ folder

- Disk4: 750GB

- Disk5: 1TB

 

 

I'm figuring out two possible solutions:

1.- To stop using Disk1 for backups (I have a 2.5" usb disk that will solve it for now) and move all the data from Disk3 to Disk1.

2.- Replace Disk3 using Disk1.

 

I've tried moving /appdata and the docker.img file and folder to Disk1 but I don't have the right permissions, so I'm not sure if that's the right way to do it.

About option 2, I'm not totally sure about the steps to do it minimizing risks. Should I first empty disk1 and remove it from the array and then replace it for Disk3 role?

 

Help would be much appreciated :( 

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On 4/19/2019 at 7:11 AM, almarma said:

I have a disk (disk3) which seems to be slightly damaged.

 

Ditto. Ironically, mine was Disk 3 as well and I lost the entire disk; long story, but it was no fault of unRAID. (Thanks again Johnathan for helping me recover what I could as best I could.)

 

Anyways, I would prioritize what would be the hardest to recover and keep that stuff on the array freespace and whatever is easiest to recover on an external HDD (assuming you have one) If you're comfortable with the Krusader docker that will be a good tool to assist.

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5 hours ago, almarma said:

I'm figuring out two possible solutions

Let me just give an outline and we can fill in some of the details as we go:

  1. Make any backups you need onto that 2.5" USB disk so you can make room on disk1 for the disk3 contents.
  2. Copy disk3 contents to disk1. Might have to go to the command line for this.
  3. New Config to remove disk3 and rebuild parity.

 

 

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12 hours ago, trurl said:

Let me just give an outline and we can fill in some of the details as we go:

Thank you very much for the follow up

 

12 hours ago, trurl said:

Copy disk3 contents to disk1. Might have to go to the command line for this.

 

Ok, this is the point where I want to be sure I do it right. I know some basic Linux command line tools, but it has been a while since the last time. Isn't unBalance a good tool to do it?

Also, I guess the Docker should be down before proceeding. Should the array be down too? I want to be sure before doing any step to minimize stress and errors along the way.

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I have a question: Let's say for simplicity that I have one share called MOVIES assigned to use Disk1 Disk2 and Disk3, and then with the array down, I change its settings to use only Disk1 and Disk2. Will the content be automatically moved from Disk3 to the other 2 to remove the content from Disk3? I know how it goes adding disks, but not how it goes removing them from shares

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5 minutes ago, almarma said:

Isn't unBalance a good tool to do it?

Also, I guess the Docker should be down before proceeding. Should the array be down too?

Unbalance might be OK, try it. If some of it doesn't get moved we can try to deal with that another way.

 

Disable the docker and VM services (the individual dockers or VMs are not enough) in Settings - Docker and Settings - VM Manager.

 

The array has to be up for the disks to be accessed.

2 minutes ago, almarma said:

I have one share called MOVIES assigned to use Disk1 Disk2 and Disk3, and then with the array down, I change its settings to use only Disk1 and Disk2. Will the content be automatically moved from Disk3 to the other 2 to remove the content from Disk3?

All user share settings only affect where new files are written. Nothing ever gets moved automatically except between cache and array according to the use cache setting. Regardless of the Include/Exclude settings, all disks are considered when reading files for a share. If the share has files on a disk they will be part of the share for reading. The user shares are simply the top level folders on cache and array disks.

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OK. My progress so far:

 

  • I was able to empty Disk1 totally.
  • I was able to copy Docker.img and /appdata/ from Disk3 to Disk1 (using Dolphin Docker with root access. I copied, I didn't remove anything from Disk3 yet). Yes, I was using a docker app with the docker system still up, but because I just copied it, it seems it worked.
  • Next I shut down Docker service, changed settings to Disk1
  • Then I changed the share location to use Disk1 instead of 3.
  • I turned on Docker service and checked one by one all the apps and modified its settings to use Disk1 if I saw any path using Disk3.

 

Everything seems to be working fine, and this was in my opinion the most critical part. Next I'll try:

  • to rename Docker.img and /appdata/ folders (adding .backup or something) to see if nothing crashes and it's yet stable.
  • Then I'll restart the Docker service to confirm the old folders are not used at all.
  • And then I plan to reboot the server for same goal.

If all goes as planned, I'll move the rest of the folders out of Disk3 and rebuild the array without it.

Does it sounds fine? Am I missing some step?

 

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1 hour ago, almarma said:

Next I shut down Docker service, changed settings to Disk1

Instead of specifying a specific disk for settings, it is a lot more flexible, and more "standard", to specify a user share. Then you don't have to go to a lot of different settings and change them each. If you want it to use a specific disk, you just make the user share uses a specific disk, and if necessary, move files to that disk, but you don't have to change any settings for the location of docker image or other things.

 

For example, I noticed in your docker.cfg you specified /mnt/disk3/appdata for the appdata path. It would be better to just use /mnt/user/appdata. Etc.

 

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3 hours ago, trurl said:

Instead of specifying a specific disk for settings, it is a lot more flexible, and more "standard", to specify a user share.

I agree with you. The only reason why I did that was because the "Fix Common Problems" recommended it to me. I had it as a user share but it told me it wasn't recommended :( 

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