ちなみにgmirror list の結果っす
Geom name: mrr0
State: DEGRADED
Components: 2
Balance: split
Slice: 4096
Flags: NONE
GenID: 0
SyncID: 1
ID: 2852835355
Providers:
1. Name: mirror/mrr0
Mediasize: 250058267648 (233G)
Sectorsize: 512
Mode: r2w1e3