ZFS Label & Data recovery

subcool · January 16, 2016, 5:12am

Hey,
I am a noob to this forum, and ZFS, Freenas.
i Had recently watched your Data Recovery segment on Youtube:

I was interested watching it, but there were a bit of gaps on the recovery portion.
My Major concern is trying to retrieve my zfs labels from my pool so i may recover my data.
I hijacked a thread on bsdforums:

forums.freebsd.org

ZFS - Need help to recover data from damaged ZFS po...

AndrewS If the command dd if=<zfs partition> | strings |grep pool_guid does not return "pool_guid" string, I don't think the pool is recoverable. The...

Which details the issue I am trying to recover from, and what appears from others.

I ran across a thread that suggested using this:

gist.github.com

https://gist.github.com/jjwhitney/baaa63144da89726e482

instructions.txt

Originally written by Jeff Bonwick (http://www.mail-archive.com/[email protected]/msg15748.html), and updated by James Lee to work with modern ZFS libs (https://www.mail-archive.com/[email protected]/msg47316.html), I was able to compile this life-saving utility in Ubuntu 14.04 and have verified that it works. (I'm using ZFSonLinux.)

Download the ZFSonLinux tarball and replace the cmd/zhack/zhack.c file with "labelfix.c". Note that zhack is just a simple utility that we're replacing so that we don't have to setup the build environment. (It's hard, so we'll reuse the good work of the ZFSonLinux people.)

Run "./configure; make" and if all goes well then the zfs tools will be built, except for zhack, which we replaced. Run that with the device path to recover your data.

If you want to be super-careful and not tamper with your disk, you can clone it and run the utility on your clone. Or, create an overlay as described in this page: https://raid.wiki.kernel.org/index.php/Recovering_a_failed_software_RAID#Making_the_harddisks_read-only_using_an_overlay_file

labelfix.c

#include <devid.h>
#include <dirent.h>
#include <errno.h>
#include <libintl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stddef.h>

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And i finally got it kinda working on a ubuntu USBlive flash drive, but i didnt get into using it to recover anything. With the confusion and concerns of what might disrupt my data, i rebooted back into Freenas. But when i did, Freenas wasnt very happy. Somehow my disks ended up full, it didnt recognize my new zfs pools and required 3 reboots before it would boot normally again.

All this non-sense aside. I was looking for help to retrieve my ZFS labels. If you can help or suggest anything. Please do.

Thanks!