Double hard disk replacement

[Bhoot]

I'm running a 8 drive raidz2 server with freeNas 11.2U2.
I have been running a 4tbx8 configuration and I'm upgrading to 8tb disks. Each disk is taking a little under 33 hours to resilver.
Now the problem I'm facing is the 7th disk has about 32 hours to go and I've to leave my location in about 30 hours. There is no way I can delay my movement and I will miss replacing the 8th disk after resilver of 7th disk and hence the entire pool will not increase in size, which was anyways my motive for the upgrade.
My question is simple, should I start resilvering the 8th disk before end of the 7th disk? Theoretically 6 disks being upgraded should hold all data required to rebuild the pool. Also after 3 hours the 7th disk would finish resilver and I'll have the redundancy.
Has any one tired this before. I understand the risks, but again I don't Wan to sit a fortnight with limited storage.
I probably know the answer, but still would love for you guys to comment.

 

[Heracles]

Hey Bhoot,

As you said yourself, it represents a risk. Not a dramatic one but still it is one. Did you test your new drives before putting them in ? If you did not, that will increase the risk in case of a Deffective On Arrival drive. (higher probability)

How are your backups in case of problem ? If you don't have any, have some that are not complete or never tried a restore, that also increases the risk. (higher potential damage).

How bad is it to leave before the auto-expand is done ? Can you not go back or ask someone to replace the drive for you at a later time ?

At the end, you will be the one taking and assuming that risk. Up to your own appetite for that. Personally, I always managed my own setup to avoid forcing myself in such situations. I provision space long before it is require. I have a complete offsite backup and I test my restore procedure a few time every year. I avoid that risk not to take it.

Up to you to make your own mind...

 

[Jailer]

If you have available SATA ports you can hook up the new drive without removing the old drive and resilver it in place without losing redundancy.

 

[Bhoot]

Just out of curiosity. If I start such a task would it dramatically slow down replacement of both disks?
Say I have disk A complete to 80% and I replace disk B, so now will disk A rebuild itself first or will disk B also start resilvering, thus increasing the over all time of 0 redundancy?

~SNIP~

I agree to almost every thing you say. I also like to keep this server handled by one person (me), so that any thing that goes wrong is blamed on me. Else I would always find someone else sabotaging the server everytime something goes wrong.
With the same effort I will not let anyone else do the replacement task. I am still trying to squeeze the travel itinerary so that I can start the replacement before I start. I do have critical files backed up, but a lot of them ain't. I guess having a 20.0TiB server running for the family has it's own disadvantages. Now it's going upto 40 TiB :-|

~SNIP~

I do have SATA ports, but no extra space to keep the hard disk. Also don't want to "hang" it somewhere and risk the shaking/drop while the resilver is on.