If Boot Pool and/or System Dataset die during a RUNNING system, risk of corruption to storage pools?

[winnielinnie]

Currently, my boot-pool lives on a single 64GB SSD. I have also relocated my System Dataset, logs, and reports to this boot-pool.

I understand the risks of logging and reporting to an SSD: these drives have limited write cycles. What I have also read is that this risk is usually over-exaggerated, considering that it takes a LOT (as in a LOT, LOT, LOT) of data being constantly written to kill an SSD, and that the drive's controller already spreads out the writes over its entire capacity.

My question is more specific to FreeNAS. Will a boot drive failure (or system dataset) failure on a live system negatively effect or corrupt the user's storage pools?

As it stands now, is there anything outside of a ZFS storage pool's metadata that relies on anything living inside the system dataset or boot-pool? If, for some reason, I suddenly yank out my boot drive (essentially simulating sudden failure of my system dataset and boot-pool during a live running system), will it cause corruption to my storage pools? Does the risk of irreversible corruption increase if my storage pools were in the middle of reads/writes through an SMB share? Is this any different than ZFS resiliency through an electrical power outage?

 

[anmnz]

The answer to each of your questions is "no".

Your ZFS "storage pool" does not rely in any way on the boot pool or on the FreeNAS system dataset. And it is a fundamental design feature of ZFS that the on-disk format is always consistent. You cannot corrupt it by cutting power.

 

[winnielinnie]

Thank you much for clearing this up, anmnz! Searching around the web yielded vague answers. I read someone warning another that if their System Dataset fails on a live running system, it can cause corruption to the storage pools.

But I'm glad to know such ZFS pools are fully independent of the System Dataset.

 

[danb35]

I read someone warning another that if their System Dataset fails on a live running system, it can cause corruption to the storage pools.

That would be a very ignorant individual. It can (and almost certainly will) cause a system panic, but it wouldn't affect your storage pool(s).