FreeBSD 9.0-R系をこっそり入れてみた。

職場に２台あるサーバ機 (DELL PowerEdge SC440) に入れてみました。
ATAがCAMに統合された都合で、SATA HDDのマウント番号が不思議なことになっています。

PC1% dmesg | grep ada
ada0 at ata2 bus 0 scbus1 target 0 lun 0
ada0: <WDC WD800AAJS-18TDA1 01.00A04> ATA-7 SATA 2.x device
ada0: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes)
ada0: 76293MB (156250000 512 byte sectors: 16H 63S/T 16383C)
ada0: Previously was known as ad4
ada1 at ata2 bus 0 scbus1 target 1 lun 0
ada1: <INTEL SSDSA2CW160G3 4PC10362> ATA-8 SATA 2.x device
ada1: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes)
ada1: 78125MB (160000000 512 byte sectors: 16H 63S/T 16383C)
ada1: Previously was known as ad5
ada2 at ata3 bus 0 scbus2 target 0 lun 0
ada2: <Hitachi HDS721010CLA332 JP4OA3MA> ATA-8 SATA 2.x device
ada2: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes)
ada2: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
ada2: Previously was known as ad6
ada3 at ata3 bus 0 scbus2 target 1 lun 0
ada3: <Hitachi HDS721010CLA332 JP4OA3MA> ATA-8 SATA 2.x device
ada3: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes)
ada3: 953869MB (1953525168 512 byte sectors: 16H 63S/T 16383C)
ada3: Previously was known as ad7
Trying to mount root from ufs:/dev/ada0p2 [rw]...

PC2% dmesg | grep ada
ada0 at ata2 bus 0 scbus1 target 0 lun 0
ada0: <WDC WD800AAJS-18TDA1 01.00A04> ATA-7 SATA 2.x device
ada0: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes)
ada0: 76293MB (156250000 512 byte sectors: 16H 63S/T 16383C)
ada0: Previously was known as ad4
ada1 at ata3 bus 0 scbus2 target 0 lun 0
ada1: <ST3500630NS 3.AEG> ATA-7 SATA 2.x device
ada1: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes)
ada1: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
ada1: Previously was known as ad6
ada2 at ata3 bus 0 scbus2 target 1 lun 0
ada2: <ST3500630NS 3.AEG> ATA-7 SATA 2.x device
ada2: 300.000MB/s transfers (SATA 2.x, UDMA5, PIO 8192bytes)
ada2: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
ada2: Previously was known as ad7
Trying to mount root from ufs:/dev/ada0p2 [rw]...

PC1には４ポートあるSATAすべてにHDD(SSD)が搭載されていて、PC2は4ポート中1ポートが空いている状況なのですが、ada0～3 と ada0～2 という具合に連番になっていますね。
PC2のほうでは、ada0, 2, 3 になるのかと思ってました……
関係しそうな GENERIC カーネルの設定はこれかな？

device          ahci            # AHCI-compatible SATA controllers
device          ata             # Legacy ATA/SATA controllers
options         ATA_CAM         # Handle legacy controllers with CAM
options         ATA_STATIC_ID   # Static device numbering

ATA_STATIC_IDついてるのに……そういうものなんでしょうか。