Owner's Manual

Installation Instructions and Important Information 27
To work around the issue, pass the following parameter to the kernel
command line at system boot:
noexec=off
A fix for this issue is available in Red Hat Enterprise Linux 4 Update 7.
DRAC 4 Virtual CD Drive Reset May Cause System Instability
The use of the default ide-cd driver may cause system lockups when a Dell
Remote Access Controller 4 (DRAC 4) reset occurs. A workaround for this
issue is to use the ide-scsi driver to control the virtual CD device on systems
with the DRAC 4. To do so, pass the following parameter to the kernel
command line:
hdX=ide-scsi
where X identifies the virtual CD device letter. You can find the virtual CD
device letter by reading the /proc/ide/hdX/model files until you locate the
value for VIRTUALCDROM DRIVE.
While using the ide-scsi driver, the operating system can take the CD device
offline when a RAC reset occurs. The device can be brought back online, in
the usual manner for SCSI devices, by typing the following commands in a
console:
echo "scsi remove-single-device Y 0 0 0" >
/proc/scsi/scsi
echo "scsi add-single-device Y 0 0 0" >
/proc/scsi/scsi
where Y is the SCSI host number of the virtual CD device, which can be
found by reading the /proc/scsi/scsi file and finding the line "Host:
scsiY" that corresponds to the virtual CD.
NOTE: A defect in the sr_mod (the SCSI CD-ROM driver), which is included with the
initial release of Red Hat Enterprise Linux 4, prevents these commands from
working correctly. A corrected driver may be available in Red Hat Enterprise Linux 4
Update 2. If the driver is not available, install the DKMS sr_mod driver that was
included with your system.
A fix for this issue is available in Red Hat Enterprise Linux 4 Update 7.
RHELIIG.book Page 27 Thursday, April 14, 2011 12:15 PM