Disk name changed


Recommended Posts

Ok bare with me here!

 

This was my first server a r710 and I upgraded the raid controller to a h700 to make it 4tb+ compatible. Then I wanted to try unraid. I know it was wrong at the time, but I couldn't get the drives to show up individually (or at all from memory). What I ended up doing through the raid config was created a virtual drive for each drive and this made them show up in unraid. Like I said it probably isn't the ideal way but it worked and it was a great way to test unraid. Safe to say I was hooked on unraid and just left everything as is got everything installed and never looked back until last night when I drive failed.

 

Now I should have checked the wiki first but I didn't. I shut down and pulled the drive. Turns out that wasn't the right drive. put it back in and pulled another drive, that wasn't it either. Third times a charm, I pulled it and then thought he I should just put it back in in case it wasn't seated right or something. So I slid it back in and booted and its fine. The raid config has now given these 3 drives new names for the virtual drives (the numbers at the end have changed, PERC_H700_00e9755f0db018542100ef70de90f648_36848f690de70ef00215418b00d5f75e9 for example) and now unraid just shows up 'wrong' when I try assign the drives. Also, one of the drives is the parity drive!

 

I can't find a way to rename the drives to what they should nor can I force unraid to just accept it. Unless there's another way I'm not aware of. Do I mount these drives as new drives or will that erase them? I just need the backups off it because I only just started doing backups and hadn't set a spot to move them out of the array yet of course. At this point I assume I'll have to wipe everything and start over.

 

Any help would be appreciated.

Link to comment

That's one of the reasons raid controllers are not recommended.

 

You can do a new config, assign all disks as data drives and start the array, you should get one unmontable disk and that will be your parity, if you get more than one grab and post your diagnostics, then do another new config now with parity assigned and check "parity is already valid" before starting the array, finally run a parity check since a few sync errors are expected.

  • Like 1
Link to comment
25 minutes ago, johnnie.black said:

That's one of the reasons raid controllers are not recommended.

 

You can do a new config, assign all disks as data drives and start the array, you should get one unmontable disk and that will be your parity, if you get more than one grab and post your diagnostics, then do another new config now with parity assigned and check "parity is already valid" before starting the array, finally run a parity check since a few sync errors are expected.

 

You're beautiful and I love you. Worked great, just doing the parity check now! Much appreciated for your help!

  • Like 1
Link to comment
  • 2 years later...
  • 1 month later...

I am in a situation similar to Doc Brown's....except in my case the drive really IS toast. 

 

So I'm getting the "wrong" message with the Parity drive...and I need to replace disk 3 while I'm at it. 

 

When I go to the New Config screen, I see a scary message that says

 

"DO NOT USE THIS UTILITY THINKING IT WILL REBUILD A FAILED DRIVE - it will have the opposite effect of making it impossible to rebuild an existing failed drive - you have been warned!"

 

Is there a way to simply rename (or force UNRAID to acknowledge) the existing parity drive other than New Config?

 

If I go through with New Config  with Preserve Current Assignments == ALL, will I lose the data on the replaced Disk 3?  

Link to comment
9 hours ago, jkp1187 said:

[Yes, in retrospect, this may not have been the wisest configuration....]

No, it's not, and again, this will only work if parity is valid, please follow the instructions below carefully and ask if there are any doubts.

 

-Tools -> New Config -> Retain current configuration: All -> Apply
-Check all assignments and assign any missing disk(s) if needed, including new disk3
-Important - After checking the assignments leave the browser on that page, the "Main" page.

-Open an SSH session/use the console and type (don't copy/paste directly from the forum, as sometimes it can insert extra characters):

mdcmd set invalidslot 3 29

-Back on the GUI and without refreshing the page, just start the array, do not check the "parity is already valid" box (GUI will still show that data on parity disk(s) will be overwritten, this is normal as it doesn't account for the invalid slot command, but they won't be as long as the procedure was correctly done), disk3 will start rebuilding, disk should mount immediately but if it's unmountable don't format, wait for the rebuild to finish and then run a filesystem check

  • Like 1
Link to comment
20 hours ago, johnnie.black said:

disk should mount immediately but if it's unmountable don't format, wait for the rebuild to finish and then run a filesystem check

Okay, so followed directions as above, and it looks like it completed, but it's still showing as unmountable.

 

After stopping array and turning on maintenance mode, I do  N O T  see "Check Filesystem Status" available for Disk 3 under MAIN --> DISK 3. The section is just missing. It is available for other data disks, just not this one. 

 

This is what I am seeing in maintenance mode at the moment:

image.thumb.png.389341be0cfe542edd15c4279cf6dd0b.png

 

Am running 6.8.3. Not sure how to proceed here.

 

EDITED TO ADD: second screenshot shows that it still wants to format the drive.... Also, I have not rebooted since beginning this process, if that makes a difference.

 

image.thumb.png.4484d589bf73bb1faaa71df90193c652.png

Edited by jkp1187
Link to comment
22 minutes ago, johnnie.black said:

Looks like you used a slightly smaller disk to replace disk3:

 


Aug 26 18:00:39 ZOE-X1 kernel: attempt to access beyond end of device
Aug 26 18:00:39 ZOE-X1 kernel: md3: rw=4096, want=4000797296, limit=3907029104
 

Disk needs to be same size or larger.

 

 

Darn. Got it. 

 

I happen to have a second drive on hand, definitely larger (it is 4TB). I am going to get it connected up and rebuild that as Disk 3. Hopefully that will get this under control long enough for me to get a far more sensible system in the next month. 

 

Are there any nuances to that approach, or should the drive swap be relatively straightforward at this point? 

 

I cannot thank you enough for all of your help, by the way!

 

 

Link to comment
2 hours ago, jkp1187 said:

this is data that would've made things ugly (but not fatal) if it was lost

Parity is not a substitute for backups. And I wouldn't trust my array to USB parity in any case. Whether or not it is acceptable to have SSDs in the parity array I will let others comment on. I know there has been some discussion about whether some SSDs might actually invalidate parity.

 

SSDs in an array without parity would be fine, except they can't be trimmed. An array without parity that included some USB connections would be fine since there is nothing to keep in sync so nothing to be disabled if a disk is dropped. Don't be surprised if you have that USB parity disconnect and require frequent rebuilds.

 

And of course there is the write speed penalty. Do you know that any write to an array disk must also write parity? And parity updates are actually slower than the slowest disk involved. So write speed to those SSDs will be slower than that USB HDD parity disk.

Link to comment
On 8/27/2020 at 10:27 AM, johnnie.black said:

I would guess a standard replace and rebuild should do it, but it's something I never tried.

Yes, it worked exactly as expected - powered down to replace the drive, powered back up. Parity was renamed, re-did the NewConfig/Invalidslot process as outlined above, let it build, ran file check, all is good. Parts being ordered for a proper system unit now as opposed to this USB-frankenstein setup...

 

Out of curiosity, why did that work? What exactly was 'invalidslot' doing such that it overrode the dark "DO NOT USE THIS UTILITY THINKING IT WILL REBUILD A FAILED DRIVE" warning UNRAID provides on the NewConfig page?

 

 

Link to comment

Rebuilding a failed drive uses the parity data with the data from all the other drives to calculate the data to rebuild the failed drive.

 

New Config enables all disks again and rebuilds parity based on all the disks in the array. If a disk is missing, the parity rebuild will not include that disk. And if the disk is not missing but is returning bad data, that bad data will be part of the parity rebuild.

 

So, after New Config rebuilds parity, anything that parity had before that would have allowed a failed or missing disk to be rebuilt is no longer there.

 

Invalidslot makes New Config rebuild a specified data disk instead of rebuilding parity.

  • Thanks 1
Link to comment
1 hour ago, trurl said:

Rebuilding a failed drive uses the parity data with the data from all the other drives to calculate the data to rebuild the failed drive.

 

New Config enables all disks again and rebuilds parity based on all the disks in the array. If a disk is missing, the parity rebuild will not include that disk. And if the disk is not missing but is returning bad data, that bad data will be part of the parity rebuild.

 

So, after New Config rebuilds parity, anything that parity had before that would have allowed a failed or missing disk to be rebuilt is no longer there.

 

Invalidslot makes New Config rebuild a specified data disk instead of rebuilding parity.

Got it. And the "3 29" appended to the end means disk 3 and disk 29 are 'invalid' -- where disk 29 == parity 2 (which I don't have). I assume if I had a valid Parity 2, the command would've been 'invalidslot 3' only? 

 

 

Link to comment
  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.