itimpi

This sounds like it is something that might be quite easy to do (at least for SATA drives) in a plugin. Does anyone know if there is already a plugin (or docker)n that attempts this - if not I might look into trying to put together a plugin myself. Having said that I am sure it will end up being harder than it sounds - these things nearly always are.

Have you formatted the new drive yet (a formatted drive is not 'empty' as far as parity is concerned)? If so you will not be able to use it to replace the failed drive without data loss. Regardless the steps I outlined will at least tell you if parity is valid so I would try those anyway before doing anything more drastic.

Chances are good that if you were using non-correcting checks then parity is likely to be valid. Only way at this point I can think of to check is to: Stop array Unassign problem disk Restart array The missing drive should now be emulated. See if the emulated disk mounts and has the expected contents. If it does then you are good to go with a replacement disk. If it does not then you might have to run a check filesystem on the emulated drive. Keep the removed drive intact until you are back up and running if possible to keep some other recovery options open.

Not sure from the diagnostics if you have a drive problem or not. I would suggest that: You check the cabling (SATA and power) to the drive in case one of them is not fully seated. Run an extended SMART test of the drive (accessed by clicking on the drive in the Main tab). It takes ~ 2 hours per TB so is quite lengthy. If it fails that drive should be replaced. Report back here for next steps if the SMART step is error free.

I do not see the parity sync completing in the diagnostics. Instead I see you getting continual resets until some disks that look like disk1 and disk2 drop offline which means that there is no SMART information for those drives in the diagnostics that we can check. You mention the SATA cabling - have you also checked the power cabling? Are your sure your PSU can handle the load when all drives are active? Have you tried running an extended SMART test on disk1 and disk2?

I suggest you post you system's diagnostics zip file so we can get a better idea of how have things set and what is happening under the cover. Please also mention which share seems to be skipping which drives.

No data disk can be larger than the smallest parity drive so since you would already have 8TB drives in the array you could only add the 4TB drives as data drives.

Anything you do to the disk automatically updates parity to keep it in sync.

What about other settings such as Split Level?

It was NOT marking the new disk as unmountable - it is the emulated one. The correct handling of unmountable drives is covered here in the online documentation accessible via the ‘Manual’ link at the bottom of the GUI or the DOCS link at the top of each forum page.

The only thing I might do differently is use btrfs for the pools, but this mainly because I am familiar with it and not yet as much with ZFS as it is new to Unraid.

Are you wanting to simply physically move the drives around or rearrange the order in the Unraid GUI? If it is just the physical locations then you can move them freely as Unraid does not care how they are connected as it recognises drive by their serial numbers.

If you must use power splitters it is normally better to use molex->SATA ones if you PSU has molex connectors has molex is rated for a higher current draw.

Do you specifically need to get Unraid running or just access the disk contents? If it is only the contents it is worth pointing out that any disk from an Unraid array can be mounted on any Linux based system.

This suggest that the configuration information was not read off the flash drive. It might be worth putting it into a Windows system and let it be checked (and whole at it make a backup of the ‘config’ folder. You may get better informed feedback if you attach the system’s diagnostics zip file to your next post in this thread.

No correcting check required if 0 errors .

Only run a correcting check if you have had errors reported a non-correcting check and you are reasonably confident there is no current hardware problem. There is a good chance I would think that the non-correcting check may not report any errors the next time it is run.

It is nearly always the cabling (although very occasionally the drive). Note it can also be the power cabling if a momentary disconnect is possible (particularly when using power splitters).

SATA connection are notoriously prone to disturbance. Interestingly on my systems I get more reliable connections with non-locking SATA cables which seems counter-intuitive. You would need another non-correcting check to see if this has resolved the issue. Up to you which you treat as higher priority as the whole point of a zeroing task is that it leaves parity unchecked.

You do NOT want to run a correcting check with a disk reporting read errors as this is just likely to end up corrupting parity. This is one of the reasons we recommend that scheduled checks are set non-correcting so you only run correcting checks when you do not have any hardware errors. You might as well cancel the current check if it is still running. The SMART information for disk5 looks fine, but the syslog shows the drive getting continual resets that look like connection issues prior to starting reporting read errors. I suggest carefully reseating the cabling to the drive (both power and SATA) and then trying the check again (non-correcting).

Handling of unmountable drives is covered here in the online documentation accessible via the Manual link at the bottom of the Unraid GUI, and also every forum page has a DOCS link at the top and a the Documentation link at the bottom.

The problem is that the logs do not survive a reboot so we cannot see what lead up to the issue. You can enable the syslog server to get persistent logs.

A pool is a set of one or more disks that are external to the main Unraid array. A pool typically gets better performance than the main Unraid array. A pool can serve various functions - caching is one of them, and another is providing the working storage for docker containers as they then get better performance. Another possibility is hosting VM vdisks but you said that was not relevant to you. If a pool is single drive then it is not redundant - this is probably fine for a pool that is being used for caching as the data does not stay there for long. If a pool is hosting docker containers data then you may want a multi-drive pool set up to be redundant.

I guess the first question is to work out if you have a good backup strategy in place so that you are prepared to run without a parity drive. Just asking as it seems a waste to use the 18TB drive for parity (parity always has to be the largest drive(s))if you do not need it (could even be used as a backup drive of all the smaller HDD). The SSD’s should be used in pools external to the main array for performance reasons. Are you thinking of running VMs or only Docker containers?

The 6.13 release will solve this problem for you when you can have multiple arrays of the type currently used for the main array. No idea of timescale for that release but going on past experience I would expect to see the first release candidates by the end of this year or not long afterwards.