ZFS on SSD's - Will it Survive Sudden Powerloss?


If I’m building a machine with SSD’s as the only storage, and those SSD’s don’t have any power-loss protection, if the power is suddenly cut to the machine, there is a good chance that whatever data is in the DRAM cache of the SSD’s will be lost. My question is, with ZFS’s journaled write system, will the lost data be recognized by ZFS, or will the lost data never make it to the drive and as such will not be marked correctly written by ZFS, which would result in no data corruption?

In a nutshell, will ZFS on consumer SSD’s survive sudden power-loss with no data corruption?

power loss won’t cause corruption.
Any incomplete transactions would be discarded

You will of course loose any data in caches, as you presumed


Okay excellent, thanks!

Perhaps consider an UPS to avoid unexpected power loss :slight_smile:


We have a UPS, but we sometimes have long power outages from storms, and the UPS will eventually die. I know some ups can connect with USB, but we have too many devices connected to it for that to work.

So you connect one device to the UPS, to monitor it’s state, then use that device to send shutdown commands to everything else.


Options include:

  1. USB hub. Research carefully to make sure there aren’t reliability issues.

  2. As sgtawesomesauce mentioned Connect to a low power SBC, and have that monitor and send shutdown signals to other devices over the network. There are other things you can do with it as well.

  3. Get a network capable UPS

Or a regular device

Uhhh, I think you’ll have a bad time if you try to go multiple masters to single slave.

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Thanks for the info guys. I’ll check our existing UPS on Monday to see if it may already be networkable. And if not i’ll look into using a single machine to send shutdown commands to others.


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There actually used to be problems with older SSDs where they could be completely bricked by unclean loss of power. The OpenZFS wiki Hardware page has some good info on SSDs and power loss protection:


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