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Adding a second disk to server

# ls /dev/sd*
/dev/sda /dev/sda1 /dev/sda2 /dev/sdb

# su -
# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xd1082b01.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').

Command (m for help):

Command (m for help): c
DOS Compatibility flag is not set
Command (m for help): u
Changing display/entry units to sectors

Command (m for help): p

Disk /dev/sdb: 34.4 GB, 34359738368 bytes
255 heads, 63 sectors/track, 4177 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xd1082b01

Device Boot Start End Blocks Id System

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4):

Partition number (1-4): 1
First sector (2048-67108863, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-67108863, default 67108863):
Using default value 67108863

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

# ls /dev/sd*
/dev/sda /dev/sda1 /dev/sda2 /dev/sdb /dev/sdb1

# /sbin/mkfs.ext4 -L /backup /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=/backup
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
2097152 inodes, 8388352 blocks
419417 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
256 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

Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.

# mkdir /backup

# mount /dev/sdb1 /backup

# mount
/dev/mapper/vg_CentOS6-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
/dev/sr0 on /media/CentOS_6.0 x86_64 Disc 1 type iso9660 (ro,nosuid,nodev,uhelper=udisks,uid=500,gid=500,
iocharset=utf8,mode=0400,dmode=0500)
/dev/sdb1 on /backup type ext4 (rw)

LABEL=/backup /backup ext4 defaults 1 2

Setup GRE Tunnel

lsmod

modprobe ip_gre
Now set it to start at boot.

echo "/sbin/modprobe ip_gre > /dev/null 2>&1" > /etc/sysconfig/modules/ip_gre.modules && chmod 755 /etc/sysconfig/modules/ip_gre.modules
Create ifcfg-tun0 Configuration Files
We need to create the configuration files for the GRE tunnel. These files live alongside your CentOS network device files in /etc/sysconfig/network-scripts/

grebos.centoshowtos.org

Create ifcfg-tun0 file. Please note, the internal and external interfaces must already be configured and plugged into the correct ports for each network.

vi /etc/sysconfig/network-scripts/ifcfg-tun0
The file should look like this (except your IPs will be different)

DEVICE=tun0
BOOTPROTO=none
ONBOOT=no
TYPE=GRE
PEER_OUTER_IPADDR=216.52.2.41
PEER_INNER_IPADDR=192.168.77.253
MY_INNER_IPADDR=192.168.77.254
gresea.centoshowtos.org

Create ifcfg-tun0 file where the network interface scripts are.

vi /etc/sysconfig/network-scripts/ifcfg-tun0
The file should look like this (except your IPs will be different)

DEVICE=tun0
BOOTPROTO=none
ONBOOT=no
TYPE=GRE
PEER_OUTER_IPADDR=141.136.108.122
PEER_INNER_IPADDR=192.168.77.254
MY_INNER_IPADDR=192.168.77.253
Bring tun0 interfaces online and verify
Now that we have the configuration files setup, we will need to bring up the tunnel interfaces and verify that they came online properly.

grebos.centoshowtos.org

We’ll just use the ifup command to bring up the interfaces.

ifup tun0
Now we can verify with the ifconfig command.

ifconfig tun0
gresea.centoshowtos.org

We’ll just use the ifup command to bring up the interfaces.

ifup tun0
Now we can verify with the ifconfig command.

ifconfig tun0
Test the connection
At this point the tunnel should be online, and the machines should be able to reach one another via internal IP addresses. Lets ping each other and make sure everything looks ok – make sure your firewall isn’t dropping ICMP packets if it doesn’t work.

grebos.centoshowtos.org

Ping gresea.centoshowtos.org internal address

ping 192.168.77.253
gresea.centoshowtos.org

Ping grebos.centoshowtos.org internal address

ping 192.168.77.254

TCP Forwarding to next server

These rules should work, assuming that iptables is running on server 192.168.12.87 :

#!/bin/sh

echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -F
iptables -t nat -F
iptables -X

iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 192.168.12.77:80
iptables -t nat -A POSTROUTING -p tcp -d 192.168.12.77 --dport 80 -j SNAT --to-source 192.168.12.87

Setting up TP-LINK TL-WN725N on Raspberry PI 2 #755

The Raspberry PI 2 (Raspbian - Debian Wheezy 2015) will not detect the TP-LINK TL-WN725N on a fresh install. Even lsusb will not show the TP-LINK WIFI device until you install the drivers. It was a lot of running around to figure this out and while the guys at the Raspberry forums are very technically inclined, they were not able to explain this in over 29 pages of chatter.

wget https://dl.dropboxusercontent.com/u/80256631/8188eu-v7-20150212.tar.gz
tar xzf 8188eu-v7-20150212.tar.gz
./install.sh
reboot

Go to GUI and look for WIFI manager and set up your network accordingly :)

Good luck!

Raspberry PI 2 - Installing Iceweasel

I have been trying to install iceweasel and keep getting a error 404 when using 'apt-get install iceweasel'
So here's the fix:

sudo su
apt-get update
apt-get dist-upgrade
sync
reboot

Then after reboot
sudo su
apt-get install iceweasel

Raspberry RAM Drive for LOGS

http://www.makeuseof.com/tag/extend-life-raspberry-pis-sd-card/

Basically, you edit the /etc/fstab

tmpfs /tmp tmpfs defaults,noatime,nosuid,size=100m 0 0
tmpfs /var/tmp tmpfs defaults,noatime,nosuid,size=30m 0 0
tmpfs /var/log tmpfs defaults,noatime,nosuid,mode=0755,size=100m 0 0
tmpfs /var/run tmpfs defaults,noatime,nosuid,mode=0755,size=2m 0 0
tmpfs /var/spool/mqueue tmpfs defaults,noatime,nosuid,mode=0700,gid=12,size=30m 0 0

Save

Reboot

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