![]() After creating partitions, it’s always good habit to examine the drives for super-blocks. Then again use ‘ P‘ to print the changes what we have made.Ĭreate /dev/sdb Partition Create /dev/sdb Partition # fdisk /dev/sdcĬreate /dev/sdc Partition Create /dev/sdd Partition # fdisk /dev/sddĬreate /dev/sdd Partition Create /dev/sde Partition # fdisk /dev/sdeĥ.Choose ‘ fd‘ for Linux raid auto and press Enter to apply.Press ‘ L‘ to list all available types.Next press ‘ P‘ to print the defined partition.Define the default value by just pressing two times Enter key.Then choose ‘ P‘ for Primary partition.Please follow the instructions as shown below for creating partition. Create /dev/sdb Partition # fdisk /dev/sdb Here, we will show how to create partition on sdb drive and later same steps to be followed for rest of the drives. Now create partitions for raid on ‘ /dev/sdb‘, ‘ /dev/sdc‘, ‘ /dev/sdd‘ and ‘ /dev/sde‘ with the help of following fdisk command. We may move further to start creating RAID 6. Note: In the above image depicts that there is no any super-block detected or no RAID is defined in four disk drives. # mdadm -examine /dev/sdb /dev/sdc /dev/sdd /dev/sde Before creating a RAID drives, always examine our disk drives whether there is any RAID is already created on the disks. After installing the tool, now it’s time to verify the attached four drives that we are going to use for raid creation using the following ‘ fdisk‘ command. If you’re new to this article, let me explain that ‘ mdadm‘ is a tool to create and manage Raid in Linux systems, let’s install the tool using following command according to your Linux distribution. If you’re following our last two Raid articles ( Part 2 and P art 3), where we’ve already shown how to install ‘ mdadm‘ tool. Step 1: Installing mdadm Tool and Examine Drivesġ. This article is a Part 5 of a 9-tutorial RAID series, here we are going to see how we can create and setup Software RAID 6 or Striping with Double Distributed Parity in Linux systems or servers using four 20GB disks named /dev/sdb, /dev/sdc, /dev/sdd and /dev/sde. My Server Setup Operating System :ĜentOS 6.5 Final Setting up RAID 1 (Mirroring) in Linux – Part 3.Creating Software RAID 0 (Stripe) in Linux – Part 2.Basic Concepts of RAID in Linux – Part 1.Those who are new to RAID setup, we recommend to go through RAID articles below. In software RAID, we will won’t get better performance in RAID 6. If you want to add more disks, you can, but you must have dedicated raid controller. Minimum 4 numbers of disks are required to create a RAID 6. Reading will be better than RAID 5, because it reads from multiple disk, But writing performance will be very poor without dedicated RAID Controller.We can rebuilt from parity after replacing the failed disk. No data loss, even after two disk fails.Will loose a two disks capacity for using parity information (double parity).RAID 6 is expensive, as it requires two independent drives are used for parity functions.In every higher environments with high availability for database, they use RAID 6 because database is the most important and need to be safe in any cost, also it can be useful for video streaming environments. Hmm… those who raise this question need to know that, if they need high fault tolerance choose RAID 6. Now, many of us comes to conclusion, why we need to use RAID 6, when it doesn’t perform like any other RAID. RAID 6 have multiple disks even in some set it may be have some bunch of disks, while reading, it will read from all the drives, so reading would be faster whereas writing would be poor because it has to stripe over multiple disks. To setup a RAID 6, minimum 4 numbers of disks or more in a set are required. Here in RAID 6 even if we loose our 2 disks we can get the data back by replacing a spare drive and build it from parity. Don’t expect extra performance than any other RAID, if so we have to install a dedicated RAID Controller too. In our earlier article, we’ve seen distributed parity in RAID 5, but in this article we will going to see RAID 6 with double distributed parity. It’s alike RAID 5, but provides more robust, because it uses one more disk for parity. Mission critical system still operational incase of two concurrent disks failures. RAID 6 is upgraded version of RAID 5, where it has two distributed parity which provides fault tolerance even after two drives fails.
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