xscsiha - probe and control scsi buses accessed using the
SGI linux-xscsi subsystem.
SYNOPSIS
xscsiha [-lprtTws] [-D debuglevel] [-L targetID|all]
[-S targetID|all] {{bus} ...
DESCRIPTION
xscsiha is used to perform operations on fibrechannel
loops of SCSI devices and parallel SCSI buses.
The following options apply to both parallel SCSI and
fibrechannel SCSI:
-p Probe for devices on the bus or loop. On parallel
SCSI buses, this option causes the driver to look
for devices at every ID on the SCSI bus. On
fibrechannel SCSI loops, this option causes the
driver to look for devices at every ID that was
reported in use at the most recent loop initializa
tion. On parallel SCSI buses, when a device is
found at lun 0, all other luns are then probed.
When devices or luns are not valid, a warning mes
sage may be printed on the console. With
fibrechannel, the Report Luns SCSI command is used
to determine which LUNs are valid. If the Report
Luns command returns error, only LUN 0 is assumed
to be valid.
-r Perform a SCSI bus reset and/or reset host adapter.
This affects all devices on that SCSI bus, causing
current commands to be aborted, and specially set
parameters to be reset, in many cases. Tape drive
state will be reset after this, and any tape opera
tions in progress will be aborted.
This option should therefore be used with some cau
tion. In very rare cases, it may cause a device to
become unusable without a powercycle. There are
times when it is desired to reset devices or
adapters that appear to be hung, however, so this
function is provided. Some host adapter drivers
will reset the adapter as part of this ioctl.
Fibrechannel adapters will perform loop initializa
tion, making this operation similar to the -l
option, except that the adapter will also be reset.
-D debuglevel
Set the debug level in the host adapter driver.
Where supported, this option changes the verbosity
of a given host adapter driver. In general, 0 is
least verbose, with no specific upward limit.
adapters:
-t Return interesting SCSI bus and attached target
parameters. Bus parameters include whether the bus
is single-ended or differential, the SCSI host ID
and the selection timeout. The target parameters
include whether the device is capable of operating
in narrow or wide mode, whether it's capable of
doing synchronous transfer and if so, what the
period and offset is.
The following options only apply to Fibrechannel SCSI
adapters:
-l Perform loop initialization. During loop initial
ization, all devices on the loop will attempt to
acquire a target ID. SGI devices will attempt to
get the ID they have been selected for, either by
settings on and position within an enclosure, or by
dials/switches on the device. If multiple devices
have the same ID selection, only one device will
get that ID. Other devices will attempt to acquire
IDs not in already in use.
This option may have a side effect of aborting cur
rent commands outstanding on the adapter, so it
should be used with care. The disk driver will
typically reissue the aborted commands, but there
will be a performance impact while commands are
reissued.
-L targetID
Send LIPRST to the specified device and then per
form loop initialization. This option is much like
-l above, except that it also requests that the
device resets itself. Not all devices will honor
the request. RAID controllers typically don't
while disk drives typically do. This option can be
used in rare cases where a device is not function
ing properly, but is still able to complete loop
initialization and acquire a target ID. For exam
ple, if a drive gets timeouts on attempts to probe
(using the -p option above), then this option may
bring it back to working condition. In this
respect, the -L option can be used for reasons sim
ilar to -r on parallel SCSI buses.
-L all This option is like the -L option directly above,
except that it directs all devices to reset them
selves. Only devices that implement FC-AL-2 or
later will respond to this. This option can be
used if a loop is malfunctioning, and it is
the malfunction, but it isn't known which. RAID
controllers typically don't honor the "self-reset"
function of the LIPRST
The -L options may have a side effect of aborting
current commands outstanding on the adapter, and it
if the device honors the reset function, outstand
ing commands to it will be dropped. The disk
driver will typically reissue the aborted commands,
but there will be a performance impact while com
mands are reissued and while a device resets.
-T Display a listing of targets connected to the
fibrechannel adapter.
-w This option will print the portname (sometimes
known as the World Wide Name) of the fibrechannel
adapter.
-s This option will print the link error statistics of
the fibrechannel adapter. The link error statis
tics will be displayed with an asterix before
adapter loop id (in case of loop topology) or
before the adapter portname (in case of fabric
topology).
-S targetID
This option will print the link error statistics of
the specified fibrechannel target. The target ID
can be either unit number (in case of loop topol
ogy) or nodename (in case of fabric topology).
-S all This option will print the link error statistics of
the fibrechannel adapter and all the targets con
nected to it.
EXAMPLES
To reset a bus carrying a scsi adapter accessed under the
SGI xscsi subsystem, use commands of the form:
xxssccssiihhaa --rr //ddeevv//xxssccssii//ppccii0011..0088..00//bbuuss
To probe the scsi bus , use commands of the form:
xxssccssiihhaa --pp //ddeevv//xxssccssii//ppccii0011..0088..00//bbuuss
FILES
/dev/xscsi/pci*/bus the scsi bus operation devices
SEE ALSO
xscsicontrol(8), xscsiadminswap(8), xscsiquiesce(8).
This command is normally usable only by the superuser,
because the standard permissions of the devices in
/dev/xscsi/* restrict access to other users.
With Fibrechannel adapters, if a loop is broken after a
system has been operational, numerous attempts will be
made to reinitialize the loop, after which the host
adapter driver will give up on the loop. At this point,
if the hardware condition causing the broken loop is fixed
(box of drives powered back on, cable reinserted, etc.),
the -r option should be used to re-establish loop opera
tion.
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