Hi my zfs is like this:
Code
Pool status (zpool status):
pool: MEGADRIVE
state: DEGRADED
status: One or more devices could not be used because the label is missing or
invalid. Sufficient replicas exist for the pool to continue
functioning in a degraded state.
action: Replace the device using 'zpool replace'.
see: http://zfsonlinux.org/msg/ZFS-8000-4J
scan: scrub repaired 0 in 4h6m with 0 errors on Fri Nov 17 15:19:40 2017
config:
NAME STATE READ WRITE CKSUM
MEGADRIVE DEGRADED 0 0 0
raidz1-0 DEGRADED 0 0 0
scsi-S_ST3000DM001-1CH1_W1F1M0SS ONLINE 0 0 0
scsi-S_ST3000DM001-1ER1_W50347PV ONLINE 0 0 0
scsi-S_ST3000DM001-9YN1_Z1F0X86A ONLINE 0 0 0
4904463646879319943 UNAVAIL 0 0 0 was /dev/disk/by-id/scsi-S_ST3000DM001-9YN1_W1F0NV12-part1
scsi-S_ST3000DM001-9YN1_S1F0ZEBB ONLINE 0 0 0
errors: No known data errorsIs it possible to make it ONLINE without the dead drive?
The raidz1 did run with 5 x 3TB disks but would it be possible to just make it work with 4 and then just make it smaller.
I have all the data backed up somewhere else but it would be nice to be able to just tell the raidz1 only to run with 4 disks instead of copying it all back to a new raidz1.
If yes how would I do that. I think of me as a pretty tech savy guy so I am willing to do some CLI. (Putty) 
And then a second question:
If I get a 4TB disk to replace the dead 3TB disk will it then just only use the 3TB of the 4TB? Or am I wrong?