Issue:
RAID is in a degraded state, however the hard drive has not “failed” – instead is showing too many errors. As it has not failed, you cannot see which drive has the errors when viewing the list of drives.
Method:
1/ Run command:
zpool status
You will see something like this:
mirror-1 DEGRADED 0 0 0
gptid/11d64819-fb3f-11e6-86cf-001b2156178e ONLINE 0 0 0
gptid/129f1716-fb3f-11e6-86cf-001b2156178e DEGRADED 0 0 1 40 too many errors
2/ To determine which drive using the GPTID value, run this command:
glabel status
You will see something like this. Match up the GPTID and you will find the port.
Name Status Components
gptid/cc182744-c8ed-11e4-80d8-6805ca31b548 N/A da0p1
gptid/cc20510d-c8ed-11e4-80d8-6805ca31b548 N/A da0p2
gptid/102cb58e-fb3f-11e6-86cf-001b2156178e N/A ada0p2
gptid/11123fe9-fb3f-11e6-86cf-001b2156178e N/A ada1p2
gptid/11d64819-fb3f-11e6-86cf-001b2156178e N/A ada2p2
gptid/129f1716-fb3f-11e6-86cf-001b2156178e N/A ada3p2
gptid/d3d857ba-532a-11e5-8d18-001b2156178e N/A ada4p2