SOLVED How are JBOD drives uniquely identified

[mikesoultanian]

We have 80 drives in multiple JBOD enclosures connected via 3 HBAs and I was wondering how they're uniquely identified by FreeNAS. Like, let's say I swap JBOD cables between HBAs - will FreeNAS be able to still identify which drives were in which volumes?

The reason I ask is because this is a production system that I've inherited and I'd like to upgrade FreeNAS, might need to update the firmware on the HBAs, and I just want to make sure I'm not going to lose my config, and if I do and need to import the saved config, that FreeNAS will be able to sort it out. And if FreeNAS can't sort it out, that I'm able to get in somehow and get the right drives where they need to go.

Sorry if this is a totally rudimentary question, but I haven't worked with HBAs before (or much with FreeNAS) so I just wanted to gain a better understanding of how it all works.

Thanks!
Mike

 

[Rattlebattle79]

Don't worry. FreeNAS uses the gpt id from the disks and which SATA port or even HBA wouldn't matter.

 

[mikesoultanian]

Oh cool! I was messing around with my FreeNAS test VM and I changed the drive numbers and brought them back online and noticed that FreeNAS brought the volume back to a healthy state - was wondering how that worked, but your answer confirms that behavior.

So, ultimately I should be able to pull all of my drives out of the enclosure and put them back in (even in different slots), and FreeNAS will detect them and bring all my volumes back up, right?

 

[chris crude]

Storage>volume, select your volume then click the volume status icon. it will show drive names and their on/offline status. Then you can hit Storage>volume>view disks and match your name to its Serial Number. I put a sticker with the serial# on the end of a drive before i put them in their bays so i dont have to pull them all out of their bays to find the serial# on the manufacturer label when one dies.

 

[chris crude]

Oh cool! I was messing around with my FreeNAS test VM and I changed the drive numbers and brought them back online and noticed that FreeNAS brought the volume back to a healthy state - was wondering how that worked, but your answer confirms that behavior.

So, ultimately I should be able to pull all of my drives out of the enclosure and put them back in (even in different slots), and FreeNAS will detect them and bring all my volumes back up, right?

Right. Makes upgrading hardware easy.

 

[mikesoultanian]

It really does! Thanks so much for the details on that :)

 

[mikesoultanian]

Storage>volume, select your volume then click the volume status icon. it will show drive names and their on/offline status. Then you can hit Storage>volume>view disks and match your name to its Serial Number. I put a sticker with the serial# on the end of a drive before i put them in their bays so i dont have to pull them all out of their bays to find the serial# on the manufacturer label when one dies.

Yeah, this one bugs me as I can't get the indicator light to blink on our SuperMicro hardware, but I just got a barcode scanner and I'm going to scan all the drives' serial numbers and model numbers into a spreadsheet. I'm also going to update the comment field in FreeNAS with the particular bay that a drive is stored in for quick access in the event of a drive failure.

 

[chris crude]

I only have a 7 drive home setup, but if i had 80 drives i might need a scanner and spreadsheet too!

 

[Rattlebattle79]

So, ultimately I should be able to pull all of my drives out of the enclosure and put them back in (even in different slots), and FreeNAS will detect them and bring all my volumes back up, right?

You can even move your boot drives and disks to a new computer, and it will just work. Given that the hardware on the new computer is compatible with FreeNAS.

 

[Stux]

Don't worry. FreeNAS uses the gpt id from the disks and which SATA port or even HBA wouldn't matter.

I believe ZFS also uses its own labels.

So basically, serials, gptids and ZFS labels.

 

[Stux]

Don't worry. FreeNAS uses the gpt id from the disks and which SATA port or even HBA wouldn't matter.

I believe ZFS also uses its own labels.

So basically, serials, gptids and ZFS labels.

 

[Rattlebattle79]

I believe ZFS also uses its own labels.

So basically, serials, gptids and ZFS labels.

There are many ways to mount drives to a zpool, , but FreeNAS uses gptid. If you use the command zpool status it shows that the disks are mounted by gptid.

 

[Stux]

There are many ways to mount drives to a zpool, , but FreeNAS uses gptid. If you use the command zpool status it shows that the disks are mounted by gptid.

This is true.

And if you pop the drive, remove it, then re-add it, it won't let you because of the ZFS label indicating it belongs to a ZFS set. You use `zfs labelclear` in this scenario. But I find it easier to just quick wipe the drive.

And the Serial is stored with the device as well, so that you can find which physical disk to pull.