Should I Raid the Boot drive and what size should the drives be?

[shoulders]

Hi,

This question has been asked many times on the forum but the answers were always unclear because there were other issues at play.

My question is a clear one: Should I Raid my TrueNAS boot drive and what size should the boot drives be?

Notes:

• I would use TrueNAS to build the raid during installation.
• I will NOT be using the motherboard's onboard hardware RAID.
• I will be using SSD drives.
• I will be using the SATA plugs on my motherboard.

Thanks

 

[Samuel Tai]

The only "RAID" mode supported for the boot pool is mirroring. You don't need a large boot drive. 16 GB will be sufficient. Set up the mirror after installation.

 

[shoulders]

thank for the reply, but I need to know, is it a good policy to make the boot drive mirrored or is it pointless?

 

[Samuel Tai]

It's not really necessary to mirror the boot drive. It's more critical to regularly back up your config. If you have a config backup and your boot drive goes south, reinstalling to a new boot drive and then uploading your config will restore your system like it never happened.

 

[shoulders]

That clears things up. Everything is stored in the config.

Thanks

 

[danb35]

Set up the mirror after installation.

Or during installation--there's really no reason to wait until later, unless you're doing more advanced tricks like partitioning the device to use a portion of it for L2ARC or other purposes.

is it a good policy to make the boot drive mirrored

Probably, but it depends on your tolerance for downtime. As Samuel says, the config file is the important thing; if you have a backup of that (and you do, on your pool, if you can get to it--but it's better to download copies as you make significant system changes), you can restore your system to an identical state when a boot device fails. If you don't mind that downtime (however long it takes you to realize the failure, source and install a replacement boot device, reinstall TrueNAS, and upload the config file), then no, mirroring the boot devices isn't a particularly big deal. If that downtime would be a problem for you, though, a second SSD for a boot mirror is cheap insurance.