E.3.8. /proc/scsi/
The primary file in this directory is
/proc/scsi/scsi, which contains a list of every recognized SCSI device. From this listing, the type of device, as well as the model name, vendor, SCSI channel and ID data is available.
For example, if a system contains a SCSI CD-ROM, a tape drive, a hard drive, and a RAID controller, this file looks similar to the following:
Attached devices: Host: scsi1 Channel: 00 Id: 05 Lun: 00 Vendor: NEC Model: CD-ROM DRIVE:466 Rev: 1.06 Type: CD-ROM ANSI SCSI revision: 02 Host: scsi1 Channel: 00 Id: 06 Lun: 00 Vendor: ARCHIVE Model: Python 04106-XXX Rev: 7350 Type: Sequential-Access ANSI SCSI revision: 02 Host: scsi2 Channel: 00 Id: 06 Lun: 00 Vendor: DELL Model: 1x6 U2W SCSI BP Rev: 5.35 Type: Processor ANSI SCSI revision: 02 Host: scsi2 Channel: 02 Id: 00 Lun: 00 Vendor: MegaRAID Model: LD0 RAID5 34556R Rev: 1.01 Type: Direct-Access ANSI SCSI revision: 02
Each SCSI driver used by the system has its own directory within
/proc/scsi/, which contains files specific to each SCSI controller using that driver. From the previous example, aic7xxx/ and megaraid/ directories are present, since two drivers are in use. The files in each of the directories typically contain an I/O address range, IRQ information, and statistics for the SCSI controller using that driver. Each controller can report a different type and amount of information. The Adaptec AIC-7880 Ultra SCSI host adapter's file in this example system produces the following output:
Adaptec AIC7xxx driver version: 5.1.20/3.2.4
Compile Options:
TCQ Enabled By Default : Disabled
AIC7XXX_PROC_STATS : Enabled
AIC7XXX_RESET_DELAY : 5
Adapter Configuration:
SCSI Adapter: Adaptec AIC-7880 Ultra SCSI host adapter
Ultra Narrow Controller PCI MMAPed
I/O Base: 0xfcffe000
Adapter SEEPROM Config: SEEPROM found and used.
Adaptec SCSI BIOS: Enabled
IRQ: 30
SCBs: Active 0, Max Active 1, Allocated 15, HW 16, Page 255
Interrupts: 33726
BIOS Control Word: 0x18a6
Adapter Control Word: 0x1c5f
Extended Translation: Enabled
Disconnect Enable Flags: 0x00ff
Ultra Enable Flags: 0x0020
Tag Queue Enable Flags: 0x0000
Ordered Queue Tag Flags: 0x0000
Default Tag Queue Depth: 8
Tagged Queue By Device array for aic7xxx
host instance 1: {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255}
Actual queue depth per device for aic7xxx host instance 1: {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}
Statistics:
(scsi1:0:5:0) Device using Narrow/Sync transfers at 20.0 MByte/sec, offset 15
Transinfo settings: current(12/15/0/0), goal(12/15/0/0), user(12/15/0/0)
Total transfers 0 (0 reads and 0 writes)
< 2K 2K+ 4K+ 8K+ 16K+ 32K+ 64K+ 128K+
Reads: 0 0 0 0 0 0 0 0
Writes: 0 0 0 0 0 0 0 0
(scsi1:0:6:0) Device using Narrow/Sync transfers at 10.0 MByte/sec, offset 15
Transinfo settings: current(25/15/0/0), goal(12/15/0/0), user(12/15/0/0)
Total transfers 132 (0 reads and 132 writes)
< 2K 2K+ 4K+ 8K+ 16K+ 32K+ 64K+ 128K+
Reads: 0 0 0 0 0 0 0 0
Writes: 0 0 0 1 131 0 0 0
This output reveals the transfer speed to the SCSI devices connected to the controller based on channel ID, as well as detailed statistics concerning the amount and sizes of files read or written by that device. For example, this controller is communicating with the CD-ROM at 20 megabytes per second, while the tape drive is only communicating at 10 megabytes per second.
