Accidentally wiped FreeNAS-9.2.1.7 boot USB flash drive

[trionic]

I'm in the process of bringing online a new JBOD chassis to extend my FreeNAS server (chassis 1) from 24 4TB drives (held at 84% capacity) to 48 drives. I have the JBOD chassis built with the components detailed in the first referenced thread. Soon I plan to post a thread about both server and JBOD chassis builds.

All hard disk drives were removed from chassis 1 and safely stored. The FreeNAS USB boot flash drive was not removed from the motherboard's USB port. Fourteen new drives were installed into the JBOD chassis. The two chassis's SAS backplanes were connected and the system booted from a System Rescue boot USB flash drive. Testing then commenced on fourteen Western Digital 3TB hard disks.

The disks have passed a dd read test and now are being subjected to a destructive badblocks test.

When I was starting the tests, I was distracted by a colleague yapping away in my ear and I accidentally invoked badblocks on the FreeNAS boot drive, so that is now gone. I have the original IMG file used to create the boot drive and a recent enough backup of the FreeNAS configuration.

I am aware that from this position, careless stabs at recovering the situation could turn this from a safe and simple retrieval into a catastrophe. In no specific order, I think I must:

• Re-write the boot flash drive
• Boot FreeNAS
• Import the saved configuration
• Re-connect chassis 1's drives (the original pool)
• Do something from a terminal or in the FreeNAS GUI to bring the existing drives online

Some of those tasks have an obvious order but the others don't.

I'll leave extending the pool until later and first bring chassis 1 back online with the original drives. When I am ready to do that, what tasks should I perform and in what order?

Thank you for your time in reading this and for your expertise and please forgive the whiff of paranoia in this post ;)

 

[BigDave]

The documentation has specific directions for the importing of an existing pool
into a new install of FreeNAS. Since you are currently running an older version,
I would just like to point out this note from Section 2 - Page 52 of the 9.2.1.7 manual.

NOTE: it is important to use the GUI (or the console) for all configuration changes. FreeNAS® uses a
configuration database to store its settings. While you can use the command line to modify your
configuration, changes made at the command line are not written to the configuration database. This
means that any changes made at the command line will not persist after a reboot and will be
overwritten by the values in the configuration database during an upgrade.

For you this simply means that you should use the GUI to import your pool once you have installed
the same version (9.2.1.7) on to a reformatted or brand new USB flash drive.

This is part of the beauty of FreeNAS and ZFS, the OS and the data are totally separate and you can
mount your ZFS pool in a completely different machine and still have access to your data

 

[trionic]

Thank you for your reply.

Should I start the system with a vanilla FreeNAS boot stick, import the pool and then import my configuration; or start with a vanilla FreeNAS boot stick, import my configuration and then import the pool?

My concern was twofold: not having properly exported the pool, and having FreeNAS bot with a configuration which included a pool that wasn't there anymore!

 

[Bidule0hm]

Importing the configuration should automatically import your pool too after a reboot ;)

 

[trionic]

Just a quick follow-up to close this thread.

I followed all of the advice given:

• Wrote a replacement 9.2.1.7 USB stick and booted from that.
• Imported the most recent saved configuration.
• FreeNAS rebooted twice, started fine and everything appears to be as I left it.

This is all a huge relief to me as I have much time and energy invested into the contents of this server. Thank you to all who contributed advice :)

Next task is to start a scrub to verify pool integrity.