Possible to run a mirrored boot using both an SSD and a USB flash drive?

[billhickok]

3 questions. I've read some discussion about preference between booting from a single SSD or 2 mirrored USB flash drives.

1. Is it possible to get the best of both worlds: to boot from a SSD, while also mirroring the boot to a constantly plugged in USB flash drive?

If not, I am inclined to purchase a cheap 2nd SSD to run a mirrored SSD boot.

2. If I do a mirrored 2x SSD boot setup, can I use SSD's of different sizes? I already have a 32GB SSD, and looking to purchase a used 16GB off ebay to use as the mirrored drive.

3. (this Q is not 100% directly related) -- I have an older FreeNAS server I built in 2014. I recently turned it on after a long time of being inactive (months,) and updated to the newest OS version. Afterwards, I had some troubles booting, but managed to do so after some troubleshooting. I figured it might be because I have the boot installed on a single flash drive from a cheap, small-name brand. I'm thinking I should remedy this ASAP. Is there anyway to mirror an existing boot flash drive to another one without having to resilver my entire array?

 

[Sakuru]

1. Yes it's possible, but I wouldn't do it. Mixing drive types in a VDEV is bound to lead to weird performance issues.
2. Yes, but not in the order you described. You would have to back up your config and start over. You can't shrink a VDEV.
3. Yes, http://doc.freenas.org/9.10/system.html#mirroring-the-boot-device. Your boot drive is a separate pool from your main pool, so resilvering it has nothing to do with your main pool.

For #1 and #2 I recommend regularly backing up your config file. Unless you need 100% uptime it doesn't take very long to install a fresh copy of FreeNAS and upload the config.
For #3 I recommend the same. Back up the config and install a fresh copy of FreeNAS to the new drive.

 

[billhickok]

Appreciate it. In regards to #2 (and #1 for that matter,) the mirrored 2x SSD boot setup is intended for a brand new FreeNAS build I plan on putting together next week. Just wanted to make sure I won't run into any performance issues if the SSD's are of different sizes.

Just ordered this used 16GB Samsung SSD from ebay to use for the mirrored drive: http://www.ebay.com/itm/192106875854
At $10 a pop shipped, seems to be a no-brainer to go the double SSD route over flash drives.