11-27-2006
It is true that sam will validate changes to the kernel and reject illegal input. You don't need to use sam, but then the procedure varies from release to release and we do not know what release is involved here. With recent releases, the command kmtune would be used to adjust a value and kmtune also validates input.
I think malcqv is trying to understand how to recover is the new kernel does not work. That almost never happens anymore since kernel changes are vetted at input time. But you would interrupt the boot sequence and boot the previous kernel which is usually in /stand/vmunix.prev for recent releases.
10 More Discussions You Might Find Interesting
1. HP-UX
Good Day
Please couls somebody tell me how to display Configurable Kernel parameters from the command line. I am able to do it from SAM,but would like to dump the command line output to a text file so I can email it off to HP.
Kind Regards
Shawn (1 Reply)
Discussion started by: shawnbishop
1 Replies
2. UNIX for Advanced & Expert Users
Hi all,
I'm at SCO UNIXWARE 7.1.1, my system's memory is larger than dump device, I have found one kernel tunable parameter at SCO website ie SYSDUMP_SELECTIVE which tells me that if set to 1 system will dump only kernel mapped memory, but I'm not sure how to configure this parameter. As well... (2 Replies)
Discussion started by: tayyabq8
2 Replies
3. HP-UX
Hello all, Can anyone tell me the command line I can use to look at the following Kernel parameters:
nfile
maxfile
maxfile_lim
I'm using the Reflection manager connection to my Unix box so I can't use SAM. (3 Replies)
Discussion started by: impunchdrunk
3 Replies
4. HP-UX
I've been trying to find out the following parameters of our Unix box:
==>OS version
==> patch level
and the following kernel parameters
=>maxfiles_lim
=>maxvgs
=>nproc
=>msgmni
=>ncsize
=>nfile
Could someone help me how would I find the above(commands)?
Thanks,
Bhagat (1 Reply)
Discussion started by: bhagat.singh-j
1 Replies
5. HP-UX
Hi,
I'm new to HP-UX. i'm working on HP-UX 11.31 ia64 for testing our product
i could able to change the kernel parameter values and i need to add the following parameters to the parameters list
semmap = 258
nfile = 2048
msgseg = 7168
msgssz = 32
maxusers = 60
msgmap = 258
msgmax =... (4 Replies)
Discussion started by: jo09
4 Replies
6. Solaris
Hi gurus
Could anybody tell me which file is read by kernel to set its default system kernal parameters values in solaris. Here I am not taking about /etc/system file which is used to load kernal modules or to change any default system kernal parameter value
Is it /dev/kmem file or something... (1 Reply)
Discussion started by: girish.batra
1 Replies
7. Linux
Hi,
if I install a module with specific parameter, will this parameters applied next time system boots?
for exampe, I want to disable InterruptThrottleRate
modprobe e1000e InterruptThrottleRate=0
Is this parameter apllied only for this run, or this module will always use this parameter when... (2 Replies)
Discussion started by: Shedon
2 Replies
8. Solaris
Dear All,
I want to check whether all essential kernel parameters are installed in my Solaris 10 System. Is there any way to find it.
And also how to tune it.
Kindly help.
Thanks and Regards
Rj (8 Replies)
Discussion started by: jegaraman
8 Replies
9. Solaris
Dear All,
I have weblogic Portal Installed in the Server solaris 10.
How can i verify whether all the kernel parameters are available for this Software and also another question is
How to crosscheck a server ( Solaris 10 Sparc ) whether it has all the required kernel parameters.
... (2 Replies)
Discussion started by: jegaraman
2 Replies
10. UNIX for Dummies Questions & Answers
Virtual Machine running on VMWare workstation 9.2
os : RHEL 5.8
RAM : 2.5GB
Swap : 2.6gb
CPU : 1 virtual CPU
Surprizingly I couldn't find much from googling on What exactly does Kernel parameters do ?
I was under the impression that kernel parameters just set the limits/maximum for a... (2 Replies)
Discussion started by: John K
2 Replies
LEARN ABOUT DEBIAN
sg_reset
SG_RESET(8) SG3_UTILS SG_RESET(8)
NAME
sg_reset - sends SCSI device, target, bus or host reset; or checks reset state
SYNOPSIS
sg_reset [-b] [-d] [-h] [-t] [-V] DEVICE
DESCRIPTION
The sg_reset utility with no options (just a DEVICE) reports on the reset state (e.g. if a reset is underway) of DEVICE. When given a -d,
-t, -b or -h option it requests a device, target, bus or host reset respectively.
The ability to reset a SCSI target (often called a "hard reset" at the transport level) was added in linux kernel 2.6.27 . Low level driv-
ers that support target reset hopefully reset a logical unit only when given the device reset (i.e. -d) option. This should removed the
ambiguity of whether "device" meant LU or target that we have had in the past.
In the linux kernel 2.6 series this utility can be called on sd, sr (cd/dvd), st or sg device nodes; if the user has appropriate permis-
sions.
In the linux kernel 2.4 series support for this utility first appeared in lk 2.4.19 and could only be called on sg device nodes. Various
vendors made this capability available in their kernels prior to lk 2.4.19.
OPTIONS
-b attempt a SCSI bus reset. This would normally be tried if the device reset (i.e. option -d) was not successful.
-d attempt a SCSI device reset. If the device seems stuck, this is the first reset that should be tried. This assumes the linux scsi
mid level error handler is not already in the process of resetting DEVICE.
-h attempt a host adapter reset. This would normally be tried if both device reset (i.e. option -d) and bus reset (i.e. option -b) were
not successful.
-t attempt a SCSI target reset. This assumes the linux scsi mid level error handler is not already in the process of resetting the tar-
get that contains the given DEVICE.
-V prints the version string then exits.
NOTES
The error recovery code within the linux kernel when faced with a SCSI command timing out and no response from the device (LU), first tries
a device reset and if that is not successful tries a target reset. If that is not successful it tries a bus reset. If that is not success-
ful it tries a host reset. Users of this utility should check whether such a recovery is already underway before trying to reset with this
utility. The "device,target,bus,host" order is also recommended (i.e. first start with the smallest hammer). The above is a generalization
and exact details will vary depending on the transport and the low level driver concerned.
SAM-4 defines a hard reset, a logical unit reset and a I_T nexus reset. A hard reset is defined to be a power on condition, a microcode
change or a transport reset event. A LU reset and an I_T nexus reset can be requested via task management function (and support for LU
reset is mandatory). In Linux the SCSI subsystem leaves it up to the low level drivers as to whether a "device reset" is only for the
addressed LU or all the LUs in the device that contains the addressed LU (i.e. a target reset). The additional of the target reset (i.e.
option -t) should give more control in this area. The "bus reset" is a transport reset and may be a dummy operation, depending on the
transport. A "host reset" attempts to re-initialize the HBA that the request passes through en route to the DEVICE. Note that a "host
reset" and a "bus reset" may cause collateral damage.
This utility does not allow individual SCSI commands (or tasks as they are called in SAM-4) to be aborted. SAM-4 defines ABORT TASK and
ABORT TASK SET task management functions for that.
Prior to SAM-3 there was a TARGET RESET task management function. Several transports still support that function and many associated linux
low level drivers map the -t option to it.
AUTHORS
Written by Douglas Gilbert.
COPYRIGHT
Copyright (C) 1999-2009 Douglas Gilbert
This software is distributed under the GPL version 2. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR-
POSE.
sg3_utils-1.28 July 2009 SG_RESET(8)