到目前為止，我從未擁有過任何 SAS 驅動器，最近購買了 Fusion-MPT 2 控制器：
04:00.0 SCSI storage controller: Broadcom / LSI SAS2008 PCI-Express Fusion-MPT SAS-2 [Falcon] (rev 03)
以及希捷 ST10000NM002G 10TB SAS 硬碟。我已經插入所有東西，好消息是 mp3sas 模組正在檢測控制器，並且也檢測到磁碟。
壞消息是磁碟被識別為寫保護：
[ 11.078668] sd 5:0:0:0: [sda] 19532873728 512-byte logical blocks: (10.0 TB/9.10 TiB)
[ 11.082640] sd 5:0:0:0: [sda] 4096-byte physical blocks
[ 11.086516] sd 5:0:0:0: [sda] Write Protect is on
[ 11.091759] sd 5:0:0:0: [sda] Mode Sense: df 00 90 08
[ 11.093572] sd 5:0:0:0: [sda] Write cache: disabled, read cache: enabled, supports DPO and FUA
[ 11.164638] sd 5:0:0:0: [sda] Attached SCSI disk
這意味著我可以很好地讀取它，但不能向區塊設備寫入任何內容。我嘗試透過 sysfs 重置它：
# cat /sys/devices/pci0000:00/0000:00:03.1/0000:02:00.0/0000:03:00.0/0000:04:00.0/host5/port-5:0/end_device-5:0/target5:0:0/5:0:0:0/block/sda/ro
1
# echo 0 >/sys/devices/pci0000:00/0000:00:03.1/0000:02:00.0/0000:03:00.0/0000:04:00.0/host5/port-5:0/end_device-5:0/target5:0:0/5:0:0:0/block/sda/ro
bash: /sys/devices/pci0000:00/0000:00:03.1/0000:02:00.0/0000:03:00.0/0000:04:00.0/host5/port-5:0/end_device-5:0/target5:0:0/5:0:0:0/block/sda/ro: Permission denied
我還讀到，顯然對於 SAS 驅動器，可以使用 sg-utils（特別是該sg_format工具）完成一些“格式化”，但：
# sg_format --format /dev/sda
error opening device file: /dev/sda: Read-only file system
sg_format failed: Read-only file system
這也會失敗，因為磁碟處於寫入保護狀態。我也嘗試過hdparm：
# hdparm -I /dev/sda
/dev/sda:
ATA device, with non-removable media
Standards:
Likely used: 1
Configuration:
Logical max current
cylinders 0 0
heads 0 0
sectors/track 0 0
--
Logical/Physical Sector size: 512 bytes
device size with M = 1024*1024: 0 MBytes
device size with M = 1000*1000: 0 MBytes
cache/buffer size = unknown
Capabilities:
IORDY not likely
Cannot perform double-word IO
R/W multiple sector transfer: not supported
DMA: not supported
PIO: pio0
# hdparm -r /dev/sda
/dev/sda:
readonly = 1 (on)
# hdparm -r0 /dev/sda
/dev/sda:
setting readonly to 0 (off)
readonly = 1 (on)
# hdparm -r /dev/sda
/dev/sda:
readonly = 1 (on)
我不知道是磁碟壞了，控制器壞了還是我做錯了什麼。如何使磁碟以 R/W 模式運作？