[SOLVED] Boot errors, Unable to write to cache error. Steps to resolve?


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Hi,

 

I had what I thought was a PCI bus die and drop a sata controller with one drive attached last week, and after futzing with the server for a few hours, I discovered that Unraid would only boot in GUI modes. No CLI modes will boot, and instead go on an endless reboot cycle.

 

Something's better than nothing. I rebooted in GUI mode, was thrilled to see that the SATA controller was recognized again, so I let the server rebuild the drive. That finished with no errors, so I'm back to an intact array.

 

BUT....After finishing, I started getting the error:

Unable to write to cache -> Drive mounted read-only or completely full. The main page shows my cache pool (2 512 GB SSDs) has 12.8 GB used/498 GB free. 

 

Also, all dockers are unresponsive. Ack.

 

I've seen a few threads about resolution on Reddit, but I want to be sure I'm asking here to get the most up-to-date information.

 

I suspect my Flash Drive needs replacing (hoping that will resolve boot issues), but the cache pool issue is a bit above my head.

 

Any guidance? 

 

 

 

Thanks for any help.

 

VS 

 

bender-diagnostics-20210322-1620.zip

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Thanks Jorge. Makes sense.

 

Do you know of a guide or any set of instructions for backing up and reformatting the cache pool? I've found a guide for doing so with a single cache drive, but nothing for a cache pool.

 

Thanks again.

-v 

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Posted (edited)

A followup question:

Rsync appears to have made a backup of cache pool to my backup location, but it had "chown" failures the entire time - nearly every file. 

 

Is that an issue? I suspect it will cause grief on the next rsync operation, but I'm not positive.

 

Thanks!

 

image.thumb.png.617a2fc6f5486d68b67683658072c8d7.png

Edited by Vonslappy
Added screen grab
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35 minutes ago, Vonslappy said:

but it had "chown" failures the entire time - nearly every file. 

That suggest the destination filesystem doesn't support permissions, e.g. exFAT

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Posted (edited)

Maybe the last question. I hope the last question.

 

Backup complete. No errors.

 

Stopped the array and started to change format on the Cache pool. Seems I can only change the change format to "Auto," or "BTRFS - Encrypted." Setting things to "Encrypted" naturally doesn't mount the disk because it isn't encrypted. "Auto" just spins the disk back up in BTRFS.

 

I do, however, have a giant "erase" button. Might that accomplish the same thing?

Edited by Vonslappy
Correcting my poor writing
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  • ChatNoir changed the title to [Solved] Boot errors, Unable to write to cache error. Steps to resolve?
  • JorgeB changed the title to [SOLVED] Boot errors, Unable to write to cache error. Steps to resolve?

Logs are spammed with these:

 

Mar 26 08:19:40 Bender kernel: DMAR: [DMA Read] Request device [00:02.0] PASID ffffffff fault addr 0 [fault reason 06] PTE Read access is not set
Mar 26 08:19:40 Bender kernel: DMAR: DRHD: handling fault status reg 2
Mar 26 08:19:40 Bender kernel: DMAR: [DMA Read] Request device [00:02.0] PASID ffffffff fault addr 0 [fault reason 06] PTE Read access is not set
Mar 26 08:19:40 Bender kernel: DMAR: DRHD: handling fault status reg 2
Mar 26 08:19:40 Bender kernel: DMAR: [DMA Read] Request device [00:02.0] PASID ffffffff fault addr 0 [fault reason 06] PTE Read access is not set
Mar 26 08:19:40 Bender kernel: DMAR: DRHD: handling fault status reg 2

 

Can't see anything else, please reboot and post new diags after array start.

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On 3/27/2021 at 7:44 AM, JorgeB said:

new diags after array start.

DIags are before starting the  array, you can post new ones or wait for more issues and post then.

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12 minutes ago, trurl said:

Also your system share has some files on disk1 possibly they are duplicates. See if you can get rid of those while docker is disabled.

Aw crap. Just saw this. If I re-disable docker, and root around, will a re-enable bring things back to order?

 

If not, it seems fairly trivial to delete and recreate the docker.img, so I can do that as well.

 

Thank you.

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