the following command checks if nagios is running locally

[root@scrappy nagios]# /usr/local/nagios/libexec/check_nagios -F /usr/local/nagios/var/status.dat -e 1 -C ‘/usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg’

NAGIOS OK: 1 process, status log updated 5 seconds ago

now, set in nrpe config as following on remote slave/master to verify is running. must restart nrpe on machine installed on to reread nrpe.cfg

command[check_nagios_failover]=/usr/local/nagios/libexec/check_nagios -F /usr/local/nagios/var/status.dat -e 1 -C ‘/usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg’

test nrpe remote command.

[root@scrappy nagios]# /usr/local/nagios/libexec/check_nrpe -H james -c check_nagios_failover

NAGIOS OK: 15 processes, status log updated 0 seconds ago

modify nagios.cfg on nagios slave. restart nagios.

execute_service_checks=0

enable_notifications=0

check_external_commands=1

now set crontab on slave to check for master failure.

[root@scrappy etc]# crontab -l

* * * * * nagios /usr/local/nagios/set_slave_status.py > /dev/null

Create script and modify master ip.

#!/usr/bin/python

import os

import commands

import sys

master='james'

slave='scrappy'

tmp_file='/tmp/nagios-failover-state.txt'

commandfile='/usr/local/nagios/var/rw/nagios.cmd'

now=commands.getoutput('date +%s')

email=’email@domain.com‘

out=commands.getoutput(’/usr/local/nagios/libexec/check_nrpe -H ‘+master+’ -c check_nagios_failover’)

#if not 0, then master is down.

master_return_val=out.find(’OK’)

#store state information

def failover_save_state(x):

fh=open(tmp_file,’w')

fh.write(x)

fh.close()

def sync_nagios_files():

os.system(’rsync -av ‘+master+’:/usr/local/nagios/etc/objects/* /usr/local/nagios/etc/objects/’)

os.system(’/etc/init.d/nagios reload’)

print “Master conf files synced with Slave.”

#read current state information

fh=open(tmp_file,’r')

current_state=fh.readlines()

fh.close()

current_state=current_state[0]

#enable or disable checks for hosts

#print current_state

if master_return_val <= 0 and current_state is not ‘enabled’:

if current_state==’enabled’:

print “Nagios slave (”+slave+”) is active. Nagios master (”+master+”) is down. No state change”

else:

os.system(’/usr/bin/printf “[%lu] ENABLE_NOTIFICATIONS\n” ‘+now+’ > ‘+commandfile)

os.system(’/usr/bin/printf “[%lu] START_EXECUTING_HOST_CHECKS\n” ‘+now+’ > ‘+commandfile)

os.system(’/usr/bin/printf “[%lu] START_EXECUTING_SVC_CHECKS\n” ‘+now+’ > ‘+commandfile)

os.system(’echo elvis has left the building | mail -s “[Nagios] Master Down! Slave Enabled.” ‘+email)

print “Nagios Failover enabled”

failover_save_state(’enabled’)

sync_nagios_files()

elif current_state is not ‘disabled’:

if current_state==’disabled’:

print “Nagios master (”+master+”) is enabled. No state change.”

else:

os.system(’/usr/bin/printf “[%lu] DISABLE_NOTIFICATIONS\n” ‘+now+’ > ‘+commandfile)

os.system(’/usr/bin/printf “[%lu] STOP_EXECUTING_HOST_CHECKS\n” ‘+now+’ > ‘+commandfile)

os.system(’/usr/bin/printf “[%lu] STOP_EXECUTING_SVC_CHECKS\n” ‘+now+’ > ‘+commandfile)

os.system(’echo We are all out of donuts. | mail -s “[Nagios] Master Restored. Slave Disabled.” ‘+email)

print “Nagios master restored”

failover_save_state(’disabled’)

sync_nagios_files()

make executable

[root@scrappy nagios]# chown nagios.nagios /usr/local/nagios/etc/set_slave_status.py

[root@scrappy etc]# chmod o=rwx set_slave_status.py

Rsync over NFS

#donkey:~# time rsync -av /mnt/backupserv/10gb /data/10gb
sending incremental file list
10gb

sent 10738729030 bytes  received 31 bytes  41223528.07 bytes/sec
total size is 10737418240  speedup is 1.00

real    4m19.773s
user    1m31.566s
sys     2m23.025s
#donkey:~# time rsync /mnt/backupserv/10gb /data/10gb

real    4m15.026s
user    1m26.453s
sys     2m24.837s

RSYNC direct

#donkey:~# time rsync -av backupserv:/mnt/data/10gb /data/
receiving incremental file list
10gb

sent 30 bytes  received 10738729035 bytes  33401956.66 bytes/sec
total size is 10737418240  speedup is 1.00

real    5m21.004s
user    3m6.644s
sys     2m1.376s

#donkey:~# time rsync -av backupserv:/mnt/data/10gb /data/
receiving incremental file list
10gb

sent 30 bytes  received 10738729035 bytes  32790012.41 bytes/sec
total size is 10737418240  speedup is 1.00

real    5m26.857s
user    3m5.924s
sys     2m8.372s

CP over NFS

#donkey:~# time cp /mnt/backupserv/10gb /data/

real    2m17.176s
user    0m0.024s
sys     0m57.276s

#donkey:~# time cp /mnt/backupserv/10gb /data/

real    2m16.983s
user    0m0.020s
sys     0m57.920s

*query
Automatically selected Catalog: MyCatalog
Using Catalog “MyCatalog”
Available queries:
1: List up to 20 places where a File is saved regardless of the directory
2: List where the most recent copies of a file are saved
3: List last 20 Full Backups for a Client
4: List all backups for a Client after a specified time
5: List all backups for a Client
6: List Volume Attributes for a selected Volume
7: List Volumes used by selected JobId
8: List Volumes to Restore All Files
9: List Pool Attributes for a selected Pool
10: List total files/bytes by Job
11: List total files/bytes by Volume
12: List Files for a selected JobId
13: List Jobs stored on a selected MediaId
14: List Jobs stored for a given Volume name
15: List Volumes Bacula thinks are in changer
16: List Volumes likely to need replacement from age or errors
17: List Volumes Bacula thinks are eligible for the changer
18: List Volumes by Volume:
19: List Volumes by Jobs:
20: List Volumes for a jobname:

apt-cache search <phrase>

Install a package

apt-get install <package>

Upgrade kernel

apt-get dist-upgrade

Set the date to Feb 1st, 2009 @ 730am.

[root@stone backups]# touch testfile2 -t 200902010730 testfile2

root@firefly:/data/music# ufw allow from 10.200.80.132 to any port 3689

Delete rule by line number.

root@firefly:/data/music# ufw delete 1
Deleting:
allow 3689
Proceed with operation (y|n)? y
Rule deleted

View current rules

root@firefly:/data/music# ufw status
Status: active

To                         Action      From
–                         ——      —-
22                         ALLOW       Anywhere
21                         ALLOW       Anywhere
3689                       ALLOW       10.200.80.132

def main():
salary1 = input(”Enter Salary #1: “)
salary2 = input(”Enter Salary #2: “)

# SET GLOBAL TO SHARE VARS
global x
global y

if(salary1 < salary2):
x=salary1
y=salary2
else:
y=salary1
x=salary2

def make_percent():
global total

total = 100-(float(x)/float(y)*100)
total=int(round(total,0))
print “Total Difference:”,total,”%”

main()
make_percent()

root@donkey:~/tech/core# python calc_number_diff.py
Enter Salary #1: 75
Enter Salary #2: 76
Total Difference: 1 %

apt-get install lvm2 dmsetup mdadm reiserfsprogs xfsprogs

Create partitions

fdisk /dev/sda

-create new partition (’n')
-change system partition type to lvm (’t')
-enter ‘8e’ for hex partition type
-write partition table to disk (’w')

Create physical volume

root@backupserv:~# pvcreate /dev/sdb1 /dev/sda2 /dev/sdc1
Can’t open /dev/sdb1 exclusively.  Mounted filesystem?
Wiping software RAID md superblock on /dev/sda2
Physical volume “/dev/sda2″ successfully created
Wiping software RAID md superblock on /dev/sdc1
Physical volume “/dev/sdc1″ successfully created

root@backupserv:~# pvdisplay
“/dev/sda2″ is a new physical volume of “903.57 GB”
— NEW Physical volume —
PV Name               /dev/sda2
VG Name
PV Size               903.57 GB
Allocatable           NO
PE Size (KByte)       0
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               zsP1EO-SlwB-nryo-gEP7-fInc-hJc4-ytVpLX

“/dev/sdc1″ is a new physical volume of “931.51 GB”
— NEW Physical volume —
PV Name               /dev/sdc1
VG Name
PV Size               931.51 GB
Allocatable           NO
PE Size (KByte)       0
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               V3RZ2b-FBsM-HoI6-aQED-ouu9-LpR1-m02VLO

Create a Volume Group
root@backupserv:~# vgcreate data /dev/sdc1 /dev/sda2
Volume group “data” successfully created

root@backupserv:~# vgdisplay
— Volume group —
VG Name               data
System ID
Format                lvm2
Metadata Areas        2
Metadata Sequence No  1
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                0
Open LV               0
Max PV                0
Cur PV                2
Act PV                2
VG Size               1.79 TB
PE Size               4.00 MB
Total PE              469780
Alloc PE / Size       0 / 0
Free  PE / Size       469780 / 1.79 TB
VG UUID               XJVXrA-m5xO-GARp-6WT0-JFlX-7ARj-jxJChV

root@backupserv:~# vgscan
Reading all physical volumes.  This may take a while…
Found volume group “data” using metadata type lvm2fdisk /dev/sda

Create Logical Volume

root@backupserv:~# lvcreate –name share1 –size 100G data
Logical volume “share1″ created
root@backupserv:~# lvcreate –name share2 –size 500G data
Logical volume “share2″ created

*run lvscan for new logical volume scan.

Format partition

root@backupserv:~# mkfs.ext3 /dev/data/share1
mke2fs 1.41.9 (22-Aug-2009)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
6553600 inodes, 26214400 blocks
1310720 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
800 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872

Writing inode tables: 192/800

Mount device

root@backupserv:~# mkdir /mnt/share2
root@backupserv:~# mount /dev/data/share2 /mnt/share2
/dev/mapper/data-share2
516061624    202652 489644572   1% /mnt/share2

Deleting an Volume Group

root@backupserv:~# vgremove data
Do you really want to remove volume group “data” containing 2 logical volumes? [y/n]: yes
Can’t remove open logical volume “share1″
root@backupserv:~# umount /mnt/share*
root@backupserv:~# vgremove data
Do you really want to remove volume group “data” containing 2 logical volumes? [y/n]: yes
Do you really want to remove active logical volume “share1″? [y/n]: yes
Logical volume “share1″ successfully removed
Do you really want to remove active logical volume “share2″? [y/n]: yes
Logical volume “share2″ successfully removed
Volume group “data” successfully removed

Delete Physical Volume

root@backupserv:~# pvremove /dev/sdc1 /dev/sdb1
Labels on physical volume “/dev/sdc1″ successfully wiped
Physical Volume /dev/sdb1 not found

ref: http://www.howtoforge.com/linux_lvm_p2

Adding Additional Disk to LVM

create fdisk LVM partition first….

root@backupserv:~# pvcreate /dev/sdb1
Physical volume “/dev/sdb1″ successfully created

root@backupserv:~# vgextend vol1 /dev/sdb1
Volume group “vol1″ successfully extended
root@backupserv:~# vgdisplay vol1
— Volume group —
VG Name               vol1
System ID
Format                lvm2
Metadata Areas        3
Metadata Sequence No  5
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                1
Open LV               1
Max PV                0
Cur PV                3
Act PV                3
VG Size               2.70 TB
PE Size               4.00 MB
Total PE              708246
Alloc PE / Size       469238 / 1.79 TB
Free  PE / Size       239008 / 933.62 GB
VG UUID               RS2K3i-SOJ8-a230-fcQL-8PX0-Bpuj-qSUYKz

root@backupserv:~# lvextend -L +930G /dev/vol1/data1 /dev/sdb1
Extending logical volume data1 to 2.70 TB
Logical volume data1 successfully resized

root@backupserv:~# resize2fs /dev/vol1/data1
resize2fs 1.41.9 (22-Aug-2009)
Filesystem at /dev/vol1/data1 is mounted on /mnt/data; on-line resizing required
old desc_blocks = 115, new_desc_blocks = 173
….

*watch more space become available with ‘watch df -h’

[root@monk ~]# tar -cvf test.tar install.log
install.log
[root@monk ~]# time find /tmp/conf-2-xp -name *.xad -exec tar –append –file=/root/test.tar {} +;
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/amd64: Permission denied
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/i386: Permission denied
find: /tmp/conf-2-xp/System Volume Information: Permission denied
tar: Removing leading `/’ from member names

real    0m15.239s
user    0m0.464s
sys     0m2.628s
[root@monk ~]# du -h test.tar
310M    test.tar
[root@monk ~]# rm -f test.tar

*delete fiel and recreate since we are appending and comparing file size after each run.

‘-exec’ using trailing ‘+’

[root@monk ~]# tar -cvf test.tar install.log
install.log
[root@monk ~]# time find /tmp/conf-2-xp -name *.xad -exec tar –append –file=/root/test.tar {} \;
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/amd64: Permission denied
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/i386: Permission denied
…
real    0m39.015s
user    0m2.739s
sys     0m21.893s
[root@monk ~]# du -h test.tar
310M    test.tar

Using xargs.

*use -print0 option to prevent whitespace issue. ‘xargs -0′ passes first argument.

[root@monk ~]# rm test.tar
rm: remove regular file `test.tar’? yes
[root@monk ~]# tar -cvf test.tar install.log
install.log
[root@monk ~]# time find /tmp/conf-2-xp -name ‘*.xad’ -print0 | xargs -0 tar –append –file=/root/test.tar;
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/amd64: Permission denied
find: /tmp/conf-2-xp/9a2f6257887d6e51f58ce2/i386: Permission denied
find: /tmp/conf-2-xp/System Volume Information: Permission denied
tar: Removing leading `/’ from member names

real    0m15.073s
user    0m0.446s
sys     0m2.774s
[root@monk ~]# du -h test.tar
310M    test.tar

Result: Using ‘+’ is two times faster than using ‘\’. -exec and xargs are about the same speed, when using ‘+’ for -exec.