[zfs-discuss] cannot import 'home': I/O error Destroy and re-create the pool from a backup source

Chris Siebenmann cks at cs.toronto.edu
Thu Apr 26 09:03:43 EDT 2018


> Can I skip a complete scan in a hope to salvage some data? Maybe the
> data I need are not spoiled by this metadata error and are still
> accessible read-only? The txg 1492684 is acceptable level of data loss
> for me (from timeline perspective).

 This is theoretically possible, although the result may not work and
may panic your machine if the problem is severe enough. There are ZFS
module parameters that control this behavior; based on looking at the
zfs-module-parameters manpage, you probably want to set both
spa_load_verify_metadata and spa_load_verify_data to 0. You can do
this after the module has loaded (but before you start the import)
by just doing:

	echo 0 >/sys/module/zfs/parameters/spa_load_verify_metadata
	echo 0 >/sys/module/zfs/parameters/spa_load_verify_data

It's possible that zdb can also tell you sufficient information to
determine which piece of metadata is corrupt, so you know what to not
look at once the pool is imported. I don't know enough about zdb to
give any suggestions on how to do this.

	- cks


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