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Cache drive forced to read only mode?

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I awoke this morning to my dockers failing to load and it seems that the primary drive of my cache pool has been forced into "Read-Only" mode.  I wouldn't be surprised if this drive is finally dying, (older OCZ SSD 128GB) but I'm at a loss for what to do.  the health checks on the drive all fail to run as well as the "Scrub" option.  

 

I'm of the belief I will need to purchase another SSD, however I'm not sure the proper process to install it without loosing my docker's and VM's.  I've attached the log file associated with the drive in question.  Is anyone able to help?

Unraid_cacheDrive.txt

  • Community Expert

Please post the complete diagnostics: Tools -> Diagnostics

  • Community Expert

There's corruption on the cache filesystem, with btrfs it's best to backup data, re-format pool and restore data, also a good idea to re-create docker image at the same time.

  • Author

Ok thank you for your reply.  What is the best way to formatt the cache pool? 

  • Community Expert

After all data is backed up, stop array and type:

blkdiscard /dev/sdX

Replace X with both devices ID, one at a time, after that start the array and you'll have the option to format the pool.

  • Author

So I went through this process and deleted my "docker.img" from the docker settings.  Now when I try to re-create my dockers I get the same type of error that the file system is read only.  

 

Error: open /var/lib/docker/tmp/GetImageBlob648374300: read-only file system

 

Any ideas?

 

 

htpc-diagnostics-20200130-1527.zip

  • Community Expert

Pool wasn't created correctly, only one device is being used and there are multiple profiles, make sure you wipe both cache devices before formatting, if you get an error with blkdiscard on any of them wiping won't work, e.g., if the controller doesn't support trim.

  • Author

So I went through it again, and it seems to be working now.  the blkdiscard command on the second SSD finishes instantly making me think it is not working.  The cache pool has the total space available as the correct SUM of the two drives, even though More drive space is being used than should be.  Are you able to confirm that both SSD's are correctly integrated into the pool?

htpc-diagnostics-20200131-0828.zip

  • Community Expert

No, still not correct, do this instead:

 

stop array

wipefs -a /dev/sdX1

wipefs -a /dev/sdX

 

replace X with cache1, then repeat both for cache2, after that start array and re-format pool.

 

  • Author

Ok,  That still didn't work.  So This is what I'm doing now:

- use "New Config" to reset cache assignments

- Using only my 256GB SDD in cache

- Using the 128GB SSD as an unassigned device (Wasn't getting more cache space from putting these in raid 0 correct?)

 

Parity is rebuilding but other than that everything seems to be working well.  

  • Community Expert
5 minutes ago, weezzer008 said:

Ok,  That still didn't work. 

That should always work, for any case, possibly wrong or missed command entered, but glad it's fixed.

 

 

  • Author

Am I correct in my belief that using these two drives in raid 0 was only coming out to 256GB? which would mean I was wasting almost 128GB of SSD space? 

  • Community Expert

Original pool was using single profile for data, so it could use full capacity, but like raid0 without redundancy.

  • Author

Now the problem is I completely forgot how to set that up.  Everything I read online states If I put these two different sized drives into the pool as raid0, it will be double the size of the smallest drive...Which would be 256GB....Meaning I would loose 128GB.

  • Author

Hi Johnnie,

 

I appreciate all of your help.  

 

In the link you sent it states: "RAID0: requires 2 device, best performance, no redundancy, if used with different size devices only 2 x capacity of smallest device will be available, even if reported space is larger." 

 

This is the only option I can see available to me with my two different sized SSD's.  I would not be able to use full capacity at 384GB with this would I? 

  • Community Expert

Just above that one, the "single" profile.

  • Author

Ah...Not sure How I missed that.  Awesome! Thank you! Now just hopefully this doesn't happen again.... not sure what happened to begin with.

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