ZFS dataset restoring

restorezfs

I have suddenly removed my ZFS dataset from ZFS pool.
I do this from GUI of Nas4Free. In logs it was command something like "ZFS destroy Main/Video". Then i recreate dataset with same name (Main/Video) and now all data, which was in this dataset is gone.
Is it possible to restore information from deleted dataset or dataset itself? I have set up daily snapshots, but, as i understand, they are stored inside dataset, so i cannot access them without restoring it's dataset.

Best Answer

Depending on how long was you pool kept online after the mistake and also how busy was the pool during this period, it might be possible to rollback it to a previous transaction group (i.e. use an older uberblock) where the file system was still present.

Here is a script that takes that approach:

http://www.solarisinternals.com/wiki/index.php/ZFS_forensics_scrollback_script

You should work on a copy of your disk(s) as the recovery attempt is destructive.

Not splitting at spaces

bash's for loop splits the argument at all whitespace characters by default. You could somehow escape each line - or simply switch to another delimiter character. cut will return one value per line, so there's a newline in between which we can choose.

Watch out for the double quotes in zfs get all, so each $dataset doesn't get split up, too.

#!/bin/bash
IFS=$'\n'
for dataset in `zfs list -H | cut -f 1`
do
  zfs get all "$dataset"
done

Resetting IFS

Afterwards, you might want to reset IFS to the value before, store it to some temporary variable.

OLD_IFS=$IFS
# the whitespaces-sensitive lines
IFS=$OLD_IFS

Best Answer

Related Solutions

View ZFS deduplication ratio on a dataset

Shell Script – Handling Whitespaces in ZFS Dataset Names

Not splitting at spaces

Resetting IFS

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