8.1. boot parameters
SCSI drivers that are built into the kernel are checked in a pre-determined
order to see if HBAs that they can control are present. The user has no
control over this order which in most cases is
arbitrary but in the case of some older ISA adapters is required to stop
misidentification
.
scsi_logging=<n>
where <n> is 0 to turn logging off
where <n> is non-zero to turn logging on
max_scsi_luns=<n>
where <n> is a number between 1 and 8 (< lk 2.4.7),
>= lk 2.4.7 the upper limit can be much larger
scsi_allow_ghost_devices=<n>
where (<n> - 1) is the maximum lu number to ghost if the
the corresponding device is offline. When <n>==0
(default) then don't ghost any devices (in lk 2.4.26
and later)
scsihosts=host0:hosts1::host3
|
The recently introduced devfs defines a "scsihosts"
boot time parameter to give the user some control over this. See the
devfs documentation [ref: W5] for a description.
The host names given in the list to the "scsihosts" boot option are
the names of lower level drivers (e.g. "scsihosts=advansys:imm::ide-scsi").
Devfs does not need to be present for "scsihosts" to be used. The
"scsihosts" parameter, if given, is echoed during in the boot up messages.
For example:
scsi: host order: advansys:imm::ide-scsi
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Also if multiple HBA are present in a system then they are scanned in
a fixed order (see footnote). The "scsihosts" parameter only effects how
these HBAs are indexed (i.e. which SCSI adapter numbers are associated with
them by the kernel). In the above example, if the "imm" driver is not found
during boot up, then the scsi adapter number "1" is not allocated. If the
"imm" driver is later loaded as a module, then it will adopt scsi adapter
number "1". If a driver that is not named in "scsihosts" is found, then
it will get the next available scsi adapter number (e.g. a built in
aic7xxx driver would get scsi adapter number "2" in the above example).
A full list of kernel parameters with some explanations can be found
in the file /usr/src/linux/Documentation/kernel-parameters.txt
.