mdwrite process on M1 takes 100% CPU

[stapoz]

Maybe someone knows the answer. What is the "mdwrite" process, can I disable it (how?) and why does it take almost 100% cpu all the time?

I have a Mac mini M1 with an external SSD drive as an encrypted backup for my time machine.

 

[appltech]

Well, I would very much like to know what each of those processes does, but I can't find any comprehensive information online.
I can only assume. "md" in mdwrite stands for metadata; other processes, like mds or mdworker, work with Spotlight, but not mdwrite. You are probably right mentioning the encrypted TM backup. From what I found, mdwrite does, or can, work for encrypting and/or writing encrypted data. Try disconnecting the Time Machine drive (and, if needed, stopping the current backup - click the Time Machine icon at the top menu > Cancel current backup) and see what happens.
Most likely, this process cannot be disabled, optimized or controlled in any way.
Please keep me posted.

 

[stapoz]

Thanks for answer. The process resides in /System/.../Metadata.framework. Unfortunately mdwrite works all the time, even when I unmount and disconnect the external backup drive. Sometimes, mdwrite cpu usage drops to few percent for a while. I'm considering to disable the backup encryption, maybe it helps. My other Macs (Intel) do not have such a problem and mdwrite takes 0.1-0.2% CPU.

 

[appltech]

Well, the backup process works not only when the TM drive is connected; it also creates mobile backups when it's not connected. So it's ready to move everything to the drive when it is connected.
I'd wait for other people to reply for a few more days, since I'm not 100% sure our conclusions are correct.