Configuring RAID level 1 on Linux using mdadm.

Configuring RAID level 1 on Linux using mdadm.

Okay, What is RAID 🙂

RAID (Redundant Array of Independent Disks) is a data storage virtualization technology.
It combines multiple inexpensive,small disk drives into an array of disks in order to
provide redundancy, lower latency and maximized the chance to recover data from the hard drives
If they crashes. And there by improving the performance.
The RAID appears to the system as a single drive.
RAID can be implemented via Hardware devices as RAID controllers or via software
controlled by the Linux Kernel.

The most commonly used RAID levels are

RAID 0 [Minimum of 2 Disk]

RAID 1 [Minimum of 2 Disk]

RAID 5 [Minimum of 3 Disk]

RAID 10 [Minimum of 4 Disk]

==============================================

 

RAID 1

RAID 1 is also known as “disk mirroring.” With RAID 1, data is copied seamlessly and simultaneously from one drive to another, creating an exact copy or mirror.
If one of the disk on raid array fails, the other can work without issues. It’s the simplest way to implement fault tolerance storage. But it slightly drag the performance.
This is useful when read performance or reliability is more important than the resulting data storage capacity.

The advantages of raid 1 are it offers excellent read speed and a write-speed that is comparable to that of a single drive and if a drive fails, data do not have to be rebuild, they just need to be copied to a new replacement drive.

The main disadvantage of RAID 1 is that the effective storage capacity is only half of the total drive capacity
because all data get written twice and software RAID 1 solutions do not always allow a hot swap of a failed drive.

Configuring RAID level 1 using mdadm.

Install mdadm on your server.
You can use the following commands to installmdadm.

For RHEL/CentOS/Fedora:
=======================

# yum install mdadm
And for Debian/Ubuntu:
=======================

#apt-get update

#apt-get install mdadm
The next step is to create a RAID array. For that create the disk partitions (with the same size) that are going to be the array members as RAID partition.
To create partitions you can use the following commands.

#fdisk -l | grep /dev/sd (This command will list the disks on the server.eg: the disks on the server are sdb & sdc)

Then choose one disk eg: sdb

#fdisk /dev/sdb

Then press ‘n’ for creating a new partition in /dev/sdb. Then press ‘p’ for use it as primary partition.
Enter the partition number. You can use the full size by just pressing two times ‘Enter key’.
Then press ‘t’ to choose the partition type. Then choose ‘fd‘ for Linux raid auto and press ‘Enter Key’ to apply it.
Pressing ‘p’ verify that the partition is created as Linux raid auto detect.
Press ‘w’ to save the changes.

Follow the same instructions to create new partition on /dev/sdc drive with the same partition size.

The next step is to create a RAID 1 sdb1,sdc1 array using command mdadm:

# mdadm –create –verbose –level=1 –raid-devices=2 /dev/md0 /dev/sdb1 /dev/sdc1

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–create–> create a new RAID device.

–verbose–>print information about its operations.

/dev/md0 is the new RAID device that we want to create.

–level–> defines the RAID level; in our case, RAID 1.

–raid-devices –> It specifies how many disks (devices) are going to be used in the creation of the new RAID device.(here 2 — /dev/sdb1 /dev/sdc1)

xxxxxxxxx
You can verify raid status using the following command.
#cat /proc/mdstat
#mdadm -E /dev/sd[b-c]1
# mdadm –detail /dev/md0
The next step is formatting the partition and creating a file system and mount the partition.
#mkfs.ext4 /dev/md0 –> to format the partition
To mount /dev/md0 to /raid1 perform the below steps.
# mkdir /raid1

# mount /dev/md0 /raid1

# df -H –> you can verify it is mounted or not.
To auto-mount RAID1 on system reboot, need to make an entry in ‘/etc/fstab‘ file.
For that add the following line to the fstab.
/dev/md0 /raid1 ext4 defaults 0 0
Then run ‘mount -a‘ to check whether there are any errors on fstab entry.
Now update /etc/mdadm/mdadm.conf or/etc/mdadm.conf file as follows:
ARRAY /dev/md0 devices=/dev/sdb1,/dev/sdc1 level=1num-devices=2 auto=yes

or

# mdadm –detail –scan >> /etc/mdadm.conf

 

That’s all for now. 🙂

How to fix Autoconfiguration IPv4 Address issue Windows Server 2012 r2

How to fix Autoconfiguration IPv4 Address issue Windows Server 2012 r2

Today when i install Windows Server 2012 r2 OS in a new HPE Proliant DL 380 server, after the os installation i have added ip manually to the Ethernet interface, but i get a Limited Access error,so i double check the ip is correct or not, i was right ip is correct, so i disabled firewall ,then i checked by typing ipconfig in the command prompt and i get result as follows

 

Ethernet adapter Ethernet:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : HP Ethernet 1Gb 4-port 331T Adapter
Physical Address. . . . . . . . . : 3C-A8-2A-F3-CF-9C
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::f0e1:58c8:4e40:4513%12(Preferred)
IPv4 Address. . . . . . . . . . . : 10.60.148.43(Duplicate)
Subnet Mask . . . . . . . . . . . : 255.255.255.224
Autoconfiguration IPv4 Address. . : 169.254.69.19(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . : 10.60.148.33
DNS Servers . . . . . . . . . . . : 10.60.148.36
10.1.12.43
NetBIOS over Tcpip. . . . . . . . : Enabled

 

as you can see there is two ipv4 ip’s , one is the ip which i given , second is APIPA range ip

 

to fix this please follow the steps

  1. Click on start and click on RUN (or simple press windowsKey+R ) type CMD
  2. type ipconfig

this is will give you following result

 

Ethernet adapter Ethernet:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : HP Ethernet 1Gb 4-port 331T Adapter
Physical Address. . . . . . . . . : 3C-A8-2A-F3-CF-9C
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::f0e1:58c8:4e40:4513%12(Preferred)
IPv4 Address. . . . . . . . . . . : 10.60.148.43(Duplicate)
Subnet Mask . . . . . . . . . . . : 255.255.255.224
Autoconfiguration IPv4 Address. . : 169.254.69.19(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . : 10.60.148.33
DNS Servers . . . . . . . . . . . : 10.60.148.36
10.1.12.43
NetBIOS over Tcpip. . . . . . . . : Enabled

now type below code in the command prompt

netsh interface ipv4 show inter

this will show you below resurlt

C:\\Users\\Administrator>netsh interface ipv4 show inter

 

Idx     Met         MTU          State                Name

—  ———-  ———-  ————  —————————

  1          50  4294967295  connected     Loopback Pseudo-Interface 1

 12          10        1500  connected     Ethernet

 13           5        1500  disconnected  Embedded LOM 1 Port 1

 14           5        1500  disconnected  Ethernet 2

 15           5        1500  disconnected  Embedded LOM 1 Port 2

 16           5        1500  disconnected  Ethernet 3

 17           5        1500  disconnected  Ethernet 4

 18           5        1500  disconnected  Embedded LOM 1 Port 3

 19           5        1500  disconnected  Embedded LOM 1 Port 4

 

 

 

check for the connected interface

from the above command result you can find the connected interface notedown its idx id which is 12 in my case but your id may vary , type following command with your idx id in the command prompt then press enter

netsh interface ipv4 set interface 12 dadtransmits=0 store=persistent

 

this will give you following result

C:\\Users\\Administrator>netsh interface ipv4 set interface 12 dadtransmits=0 store=persistent

Ok.

  1. Click on start and click on RUN (or simple press windowsKey+R ) type CMD and Type Services.msc a box will appear Search for DHCP client right click on it and Click on Properties click on Startup Type select Disable
  2. Now Click on Stop Button Below And click on Ok

* Note

  1. Unplug Your Lan Cable And Restart your System
  2. After Restart don’t Plugin your Cable, Come again to Services.msc find DHCP client right click on it and Click on Properties click on Startup Type now select Automatic
  3. Click on Start button below and then Ok.
  4. Now Plugin your Lan Cable and Enjoy.

 

Network Bonding On Centos.

Network Bonding On Centos.

 

Network interface bonding is a Linux kernel feature which allows to aggregate multiple interfaces (eth0,eth1) into one virtual link such as bond0. Network card bonding is an effective way to increase the available bandwidth. If bonded the interfaces appears as same physical device and they have same MAC address. The other names for network interface bonding are port trunking, NIC teaming channel bonding and link aggregation. The main advantage of bonded network interface is to increase data throughput by load balancing and to provide redundancy by allowing fail over from one component device to another.

## How to create a network interface bond?

Create a file named ifcfg-bondN in the directory /etc/sysconfig/network-scripts, Here “N” is the number of interfaces. Then edit the contents of ifcfg-bondn and make it similar to the configuration settings for an Ethernet interface except  that DEVICE is set to bondn instead of ethn.

For example;

DEVICE=”bond0″

IPADDR=192.168.1.121

NETMASK=255.255.255.248

NETWORK=192.168.1.0

BROADCAST=192.168.1.255

ONBOOT=yes

BOOTPROTO=none

USERCTL=no

TYPE=Ethernet

BONDING_OPTS=”bonding parameters separated by spaces”

For each interface that you want to bond, edit its ifcfg-interface file so that it contains MASTER=bondN and SLAVE entries. An example is given below.

DEVICE=”eth0″

NAME=”System eth0″

IPADDR=192.168.1.101

NETMASK=255.255.255.0

BROADCAST=192.0.2.255

NM_CONTROLLED=”yes”

ONBOOT=yes

USERCTL=no

TYPE=Ethernet

BOOTPROTO=none

DEFROUTE=yes

IPV4_FAILURE_FATAL=yes

IPV6INIT=no

PEERDNS=yes

PEERROUTES=yes

MASTER=bond0

SLAVE

Create the file bonding.conf in the directory/etc/modprobe.d/, so that it contain entry for each bonded interface, for example:

alias bond0 bonding

It ensures that the kernel loads the bonding module is loaded when bring up the bonded interface. All bonded interfaces require entry in this file.

# ip link set eth0 down >> bring interface down

# ip link set eth1 down >> bring interface down

# ip link set bond0 up >> bring interface up

HAPPY BONDING 🙂

How to remove WOUtempAdmin User Profile

How to remove WOUtempAdmin User Profile

I have got this error after updating system using WSUS Offline utility,after successful update system restarts And the login screen by default shows the username of WOUTempAdmin. Not a big deal as I can log in with my admin account. But still a pain.

to fix this issue you have to follow the steps:

Press “Windows Key” and “R

type “regedit” press Ok

Run “regedit” this will open Registry Editor

Note* Be careful when editing the registry. Don’t go into the registry editor and delete anything or change a setting unless you know exactly what you’re doing. If you do know what you’re doing and are careful to modify only the correct values, you shouldn’t have any problems. However, if you start deleting folders (known as “registry keys”) or modifying other values, you could seriously damage your Windows installation. When using the registry editor, always bear this warning in mind.

Navigate to HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon

 

Change DefaultUserName to your default user for eg: Administrator , i have used fragadmin0608 instead of Administrator this may vary

 

then within the registry you can find AutoAdminLogon

delete AutoAdminLogin

Confirm delete by pressing yes

Press F3 and search for any entry containing “woutemplogin” and delete it as long as the searchphrase can’t be found any more,then restart your system

After restart if you can see your login screen with your default username .then your issue is fixed

best of luck .

How to fix NTFS partition is in an unsafe state error in linux ?

How to fix NTFS partition is in an unsafe state error in linux ?

How to fix NTFS partition is in an unsafe state ?

 

This usually happen with recently upgraded dual bootable windows linux pc , if you upgraded to windows 8 or later you will get this error in linux

 

 

Solution

open your terninal

type

sudo ntfsfix /dev/sda3

in here /sda3 is my hdd id check error in your pc for your hdd id

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