scsi - 使用 scsi cmd 获取设备最大链接速度

Question

我正在寻找可用于获取设备最大链接功能的 scsi 命令。

我可以使用 scsi MODE SENSE（第 19 页）读取 phy 描述符并获取链接速度吗？但它与最大链接速度和协商链接速度有何不同？

Answer 1

根据SPL-4，你多使用SMP DISCOVER函数或 SCSIMODE SENSE页面19h Protocol Specific Port、子页面01h Phy Control And Discover。

对于链接速度，您应该使用NEGOTIATED LOGICAL LINK RATE. 最大链接速度是HARDWARE MAXIMUM PHYSICAL LINK RATE（物理限制）和PROGRAMMED MAXIMUM PHYSICAL LINK RATE（由PHY CONTROL功能配置）

这是使用SMP DISCOVER方式的示例：

[fge@el7 ~]$ sudo smp_discover /dev/bsg/expander-0\:0
  phy   0:T:attached:[500015535990a300:00  t(SATA)]  3 Gbps
  phy   1:T:attached:[500015535990a301:00  t(SATA)]  3 Gbps
  phy   2:T:attached:[500015535990a302:00  t(SATA)]  1.5 Gbps
  phy   3:T:attached:[500015535990a303:00  t(SATA)]  3 Gbps
  phy   4:T:attached:[500015535990a304:00  t(SATA)]  3 Gbps
  phy   5:T:attached:[500015535990a305:00  t(SATA)]  3 Gbps
  phy   6:T:attached:[500015535990a306:00  t(SATA)]  3 Gbps
  phy   7:T:attached:[500015535990a307:00  t(SATA)]  3 Gbps
  phy   8:T:attached:[500015535990a308:00  t(SATA)]  3 Gbps
  phy   9:T:attached:[500015535990a309:00  t(SATA)]  3 Gbps
  phy  10:T:attached:[500015535990a30a:00  t(SATA)]  3 Gbps
  phy  11:T:attached:[500015535990a30b:00  t(SATA)]  3 Gbps
  phy  12:T:attached:[500015535990a30c:00  t(SATA)]  3 Gbps
  phy  13:T:attached:[500015535990a30d:00  t(SATA)]  3 Gbps
  phy  14:T:attached:[50014ee5aaab876f:01  t(SSP)]  3 Gbps
  phy  15:T:attached:[500015535990a30f:00  t(SATA)]  3 Gbps
  phy  16:S:attached:[5d4ae520995f8200:03  i(SSP+STP+SMP)]  3 Gbps
  phy  20:T:attached:[500015535956633f:16 exp i(SMP) t(SMP)]  3 Gbps
  phy  21:T:attached:[500015535956633f:17 exp i(SMP) t(SMP)]  3 Gbps
  phy  22:T:attached:[500015535956633f:18 exp i(SMP) t(SMP)]  3 Gbps
  phy  23:T:attached:[500015535956633f:19 exp i(SMP) t(SMP)]  3 Gbps
  phy  24:D:attached:[500015535990a33e:24  V i(SSP) t(SSP)]  3 Gbps