Disk replacment or Treunas SCALE

i have a RAID-Z1 which is built from 4 16TB disks Lately I’ve been getting some errors in the ZFS’s zpool status (the writing part), so I decided to buy the same disk and select “replace” using the GUI

I understand that while the replacement process is running, the pool status will be degraded.
However, I’m getting also lots of errors on the disks in write. Here’s an example

Screenshot enclosed. The one in the Yellow is the original drive while the Red one is the new disk drive.

The question: should I ignore it? (I tried to run smartctl self test, all passed without any issues)

RAIDZ1 with 16TB disks is extremely dangerous. A strong recommendation is to take a full backup while you can and recreate a RAIDZ2 pool.

RAIDZ1 can survive a single disk failure.

The short answer is you should not ignore it because another failing disk and your data is gone.

Have you used the burn in script to properly test the new drive?

You can also try another sata port or cable.

Are you absolutely sure about that?

Absolutely not, as @MSameer said, get s properly burned it replacement drive and make a backup ASAP.

Which burn in script?


One of these for example, didn’t check if these resources were migrated to the new forums yet.

Leaving aside the RAID / resilvering issue, from my understanding of ZFS you would need to have some pretty unusual requirements and hardware to need L2ARC or SLOG.

Are you sure that you need these?

Just how much RAM do you have to make L2ARC useful? What is your cache hit ratio without it?

Are you doing a lot of synchronous writes that an SLOG will speed up? (If you are using SMB then an SLOG is no use whatsoever as SMB does asynchronous writes.)

Also, if your non-redundant log gets corrupted with data on it that has not been transferred to the main disks, you are going to have corrupted files. If you have synchronous writes but performance is not critical, then you will probably be better off without it.

Caveat: I am not a ZFS expert - get a second opinion.

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What’s the hardware? How are the drives attached?

This is not necessarily true. It depends on the client.

For example, macOS uses sync writes when writing to TrueNAS via SMB.

@stux Thanks. I didn’t know that.

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