Parm Patram

The usb0 NIC sometimes causes problems with certain Oracle grid components on 11g RAC.

Setting the /etc/sysconfig/network-scripts/ifcfg-usb0 ‘ONBOOT=no’ does not always work and the devices fires up again.

You can disable the NIC from even initializing by adding the following as the first line in /etc/udev/rules.d/60-net.rules
ACTION==”add”, DRIVER==”usb”, SYSFS{configuration}==”CDC Ethernet”, OPTIONS+=”ignore_device, last_rule”

tunefs.ocfs2 -S

ETHTOOL_OPTS=”autoneg off speed 100 duplex full”

Scan the fibre and re-read the device maps:
/opt/QLogic_Corporation/ql-dynamic-tgt-lun-disc-2.5/ql-dynamic-tgt-lun-disc.sh

vxdctl initdmp
vxdctl enable

vxdisk list #will show something similar to:
fas60801_40  auto            -            -            error

verify the 'FAS' number from sanlun output to make sure we are working with the correct device!

#Initialize the new disk
vxdisksetup -i fas60801_40
vxdisk list #will now show the disk online:
fas60801_40  auto:cdsdisk    -            -            online thinrclm

To create a volume in an existing disk group:
vxdg -g DGNAME adddisk DGNAME-Disk=FAS60800_27
ex: vxdg -g proddg adddisk proddg-redoDisk=FAS60800_27

# see how big we can make a concat on the new disk
vxassist -b -g proddg maxsize layout=concat proddg-redoDisk
output will be like this:
Maximum volume size: nnnnnnn (XXXXMb)

# make the volume
vxassist -b -g proddg make proddg-redoVol XXXXm layout=concat proddg-redoDisk

# mkfs.vxfs /dev/vx/rdsk/proddg/proddg-redoDisk

# then mount it up and off you go!

For a new disk group:
#Initialize the new disk group
vxdg init SOMETHING_dg SOMETHING-1=fas60801_40

vxdisk -o alldgs list
will now show the new disk in its new group:
fas60801_40  auto:cdsdisk    SOMETHING-1  SOMETHING_dg online thinrclm

#Create logical volume and filesystem

vxassist -g SOMETHING_dg make SOMETHING-vol1  SOMETHING-1

#make the filesystem
/usr/lib/fs/vxfs/mkfs -t vxfs -o largefiles /dev/vx/rdsk/SOMETHING_dg/SOMETHING-vol1

#Mount up the filesystem
mount -t vxfs /dev/vx/rdsk/SOMETHING_dg/SOMETHING-vol1 /where/ever

for i in `mount|grep nfs|awk ‘{print $3}’`; do echo -n “testing $i now…”; cd $i; ls|wc -l; cd; done

The script will need to run thru a wrapper, or the OS will ignore the setuid bit altoghether. Compile the following C program and make it setuid, and it will work:

#include 
#include 

int main(int argc, char *argv[])
{
argv[0] = "some_script_path";

setreuid(geteuid(), -1);
execv(argv[0], argv);
exit(1);
}

#!/usr/bin/perl -w
# server.pl
#--------------------

use strict;
use Socket;

# use port 7890 as default
my $port = shift || 7890;
my $proto = getprotobyname('tcp');

# create a socket, make it reusable
socket(SOCKET, PF_INET, SOCK_STREAM, $proto)
or die "Can't open socket $!\n";
setsockopt(SOCKET, SOL_SOCKET, SO_REUSEADDR, 1)
or die "Can't set socket option to SO_REUSEADDR $!\n";

# bind to a port, then listen
bind( SOCKET, pack( 'Sn4x8', AF_INET, $port, "\0\0\0\0" ))
or die "Can't bind to port $port! \n";
listen(SOCKET, 5) or die "listen: $!";
print "SERVER started on port $port\n";

# accepting a connection
my $client_addr;
while ($client_addr = accept(NET_SOCKET, SOCKET)) {
# send them a message, close connection
print NEW_SOCKET "Smile from the server";
close NEW_SOCKET;
}

mv /etc/localtime /etc/localtime-old

ln -sf /usr/share/zoneinfo/GMT /etc/localtime

hwclock –systohc (or –utc)

The problem is that the ssh session will wait for the command to complete and the ‘&’ to background the task does not seem to work. The net result is that the script running the nohup ssh command hangs.

This is because by default ssh does not allocate a TTY to run a command. You can force TTY allocation by using the ‘-t’ option to ssh, which will permit backgrounding, and the ssh command will return immediately.

In order to demonstrate, create a file /tmp/sleepy like so:

#!/bin/bash
while ( true ); do
echo `date` “sleep”
sleep 1
done

This command will invoke the script over ssh using nohup and &:

ssh -t localhost ‘nohup /tmp/sleepy &’

chage -d0 <login>