Best way to replace my (dying) cache drive with a pool of 2?

[servidude]

Running 6.10.3 here.  I have an old 1TB SSD that, surprise surprise, has started failing.  I tried rsyncing all the data off it, and did a ddrescue as well, but in both cases I got a number of read errors.  So while I have most of the data still, some of it is corrupted.

For now I have switched off Docker and VMs in order to not stress it any further.
I would like to ultimately replace the cache with a mirrored pool of two 1TB SSDs.  I believe (correct me if I'm wrong) that it will be easiest to replace the failed drive with a single new one first, and after that's working, install the additional drive and add it to the pool.

So how would I go about doing that?  I found some instructions for Replacing or upgrading your Cache drive but that seems to assume the original drive is error-free.  A link on Reddit gives instructions that seem straightforward enough, but once again they don't seem to account for the fact that I am replacing a drive with some file corruption on it.

 

So how would you proceed?  Write the ddrescue image to a new drive, and then install that as the new cache?  The problem is, there will be some files that are corrupted on it - I don't care about downloads, but if it's a Telegraf database, then that might be more of an issue.

I found a utility called ddru_findbad that parses the ddrescue log and tells you which files were affected by the read errors - this might give me an idea of what to look out for.

Note I do have "Appdata Backup" installed so could roll back from a previous version if any of my Dockers/VMs are FUBARed.

 

Thanks for any suggestions!

[JorgeB]

Copy what you can from the old SSD to the new one, any files with read errors won't be copied, so you'll know which files need to be replaced/restored, then add a member to the new pool to make it a mirror.