To reduce an UltraSCSI controller (glm), and all disks attached to
operate at Fast/Wide speed, create a file `/kernel/drv/glm.conf'
with an entry like this.
name="glm" parent="/pci@6,4000"
unit-address="2"
scsi-options=0x3f8;
name="glm" parent="/pci@6,4000"
unit-address="2,1"
scsi-options=0x3f8;
This example is for an UltraSCSI controller in slot 3 of an
Ultra Enterprise (UE)450 (pci@6,4000/scsi@2). You could also reduce
the speed to one specific disk (target) on a controller by creating
a /kernel/drv/glm.conf file with an entry like this.
name="glm" parent="/pci@6,4000"
unit-address="2"
target1-scsi-options=0x3f8;
The above would force the target 1 disk on the UltraSCSI controller in slot 3
of a UE450 to run at Fast/Wide speed and all other disks attached to this
controller would run at UltraSCSI speed.
To reduce the transfer rate for multiple targets on the same controller:
Assume there are two DLT4x00(fast SCSI, 10MB/s) tape drives attached to a
fast wide SCSI (20MB/s) controller on an e450 that is giving some SCSI
timeout errors. A solution known to work, is to reduce the transfer
rate for the two tape drives explicitly. In this example, the tape drives
are at SCSI targets 4 and 5 attached to the onboard SCSI port of the e450.
The entry below could be used to in a /kernel/drv/glm.conf file to resolve
the timeouts.
name="glm" parent="/pci@1f,4000"
unit-address="2"
target4-scsi-options=0x1f8
target5-scsi-options=0x1f8;
This method has been known to solve the following errors:
SCSI transport failed
Connected command timeout
Reducing synchronous transfer rate