What is correct procedure to replace USB stick for FreeNAS-11.1-U4 ?

[Freeman2018]

# Status:
Booting from two SanDisk Cruzer 32GB USB sticks.
Version: FreeNAS-11.1-U4

# One stick is failing:

Code:

pool: freenas-boot
 state: DEGRADED
status: One or more devices could not be opened.  Sufficient replicas exist for
		the pool to continue functioning in a degraded state.
action: Attach the missing device and online it using 'zpool online'.
   see: http://illumos.org/msg/ZFS-8000-2Q
  scan: scrub repaired 0 in 0 days 00:00:23 with 0 errors on Sat Apr 28 03:45:23 2018
config:

		NAME					  STATE	 READ WRITE CKSUM
		freenas-boot			  DEGRADED	 0	 0	 0
		  mirror-0				DEGRADED	 0	 0	 0
			18444066668970349592  UNAVAIL	  0	 0	 0  was /dev/da0p2
			da0p2				 ONLINE	   0	 0	 0

errors: No known data errors

# Assumptions about fixing issue:
* Buy new USB stick.
* Shutdown FreeNAS.
* Replace broken USB stick.
* Boot up FreeNAS, with new stick.
* Pool "freenas-boot" magically repairs itself.

# Question:
What is correct procedure to replace USB stick for FreeNAS-11.1-U4 ?

 

[dlavigne]

While that procedure does work, an alternative is to save your config, replace stick, reinstall same version to both sticks, and restore config. I prefer that method for thumb drives as it is less intensive. This method does assume that you don't want to save your previous boot envs.

 

[Freeman2018]

# The method below worked for me, in this specific use-case:
# WARNING: I am a FreeNAS/ZFS newbie.
# WARNING: Do not use this method in any other scenario or risk losing all your data.
Booting from two SanDisk Cruzer 32GB USB mirrored sticks.
Version: FreeNAS-11.1-U4
One stick is failing in boot pool: "freenas-boot".

# Checklist:
# WARNING: Do not use this method in any other scenario than described above or risk losing all your data.
* Buy new USB stick.
* Identify broken USB stick (the one with a blinking red light).
* Shutdown FreeNAS.
* Replace broken USB stick.
* Boot up FreeNAS, with new stick.
* zpool status -v (to get USB stick identifier "18444066668970349592")
* zpool offline freenas-boot 18444066668970349592
* zpool detach freenas-boot 18444066668970349592
* FreeNAS > System > Boot > Status > freenas-boot > Attach >
Member disk: da0
Use all disk space: enabled


# These links helped me figure it out:
https://forums.freenas.org/index.php?threads/freenas-11-1-unable-to-create-usb-boot-mirror.60008/
https://blog.briancmoses.com/2016/04/mirroring-the-freenas-usb-boot-device.html

# Hardware
Consumer grade parts: Asus motherboard with ECC "support" and AMD processor.