- This article explains what RAID is and how to create/manage a software RAID array using mdadm.
- Redundant Array of Independent Disks (RAID) is a storage technology that combines multiple hard disks into a single logical unit to provide fault-tolerance and/or.
- Specification Value; Lifecycle: Active: Distrib. Inventory : No: RAID-on-Chip Controller: LSISAS2108 RAID-on-Chip (ROC) RAID Management Software: MegaRAID Management.
- RAID 10 is a combine of RAID 0 and RAID 1 to form a RAID 10. To setup Raid 10, we need at least 4 number of disks. In our earlier articles, we’ve seen how to setup.
Logical Volume Management on Debian Linux. Debian Linux is a popular Linux distribution and caters to end user workstations as well as network servers.
Storage Solutions Guide. Storage products provide the building blocks for solutions that help customers understand, prioritize, store and protect critical data.
This time around, I will show you how to configure the software RAID using Debian. This also can be applied to Ubuntu system as their are based on Debian platform anyway. Do you need a file server on the cheap that is easy to setup, “rock solid” reliable with Email Alerting? RAID setup 5.1 General setup. This is what you need for any of the RAID levels: A kernel. Preferably a kernel from the 2.4 series. Alternatively a 2.0 or 2.2.
Debian is often praised for being a very stable Linux distribution. Debian’s stability paired with the flexibility of LVM makes for a highly flexible storage solution that anyone can appreciate. Before continuing with this tutorial, Tecmint offers a great review and overview of the installation of Debian 7. Aside from the easy expandability of LVM, some data resiliency features are also built into LVM.
Hybrid RAID implementations have become very popular with the introduction of inexpensive RAID controllers, implemented using a standard disk controller and BIOS.
Features such as snap- shot abilities and data migration from failing drives, provide LVM with even more abilities to maintain data integrity and availability. Setup LVM on Debian. Installation Environment. Operating System .
Root/administrative access to the system is needed. This can be obtained in Debian through the use of the su command or if the appropriate sudo settings have been configured, sudo can be used as well.
However this guide will assume root login with su. At this point the LVM2 package needs to be installed onto the system.
This can be accomplished by entering the following into the command line. At this point one of two commands can be run to ensure that LVM is indeed installed and ready to be used on the system. Check LVM Installation Status. Now that the LVM software is installed, it is time to prepare the devices for use in an LVM Volume Group and eventually into Logical Volumes. To do this the pvcreate utility will be used to prepare the disks. Normally LVM would be done on a per partition basis using a tool such as fdisk, cfdisk, parted, or gparted to partition and flag the partitions for use in a LVM setup, however for this setup two 5. RAID array called /dev/md.
This RAID array is a simple mirror array for redundancy purposes. In the future, an article explaining how RAID is accomplished will also be written. For now, let’s move ahead with the preparation of the physical volumes (The blue blocks in the diagram at the beginning of the article). If not using a RAID device, substitute the devices that are to be part of the LVM setup for . Issuing the following command will prepare the RAID device for use in an LVM setup. Once the RAID array has been prepared, it needs to be added to a Volume Group (the green rectangle in the diagram at the beginning of the article) and this is accomplished with the use of the vgcreate command.
The vgcreate command will require at minimum two arguments passed to it at this point. The first argument will be the name of the Volume Group to be created and the second argument will be the name of the RAID device prepared with pvcreate in step 3 (/dev/md. Putting all of the components together would yield a command as follows. At this point, LVM has been instructed to create a volume group called . However, at this point there still aren’t any Logical Volumes to be used for data storage purposes. Two command can quickly be issued to confirm that the Volume Group was successfully created. Now that the Volume Group is confirmed ready, the Logical Volumes themselves, can be created.
This is the end goal of LVM and these Logical Volumes are were data will be sent in order to get written to the underlying physical volumes (PV) that make up the Volume Group (VG). To create the Logical Volumes, several arguments need to be passed to the lvcreate utility. The most important and essential arguments include: the size of the Logical Volume, the name of the Logical Volume, and which Volume Group (VG) this newly created Logical Volume (LV) will belong. Putting all this together yields a lvcreate command as follows. L 1. 00. G - n Music storage.
Effectively this command says to do the following: create a Logical Volume that is 1. Music and belongs to the Volume Group storage.
Let’s go ahead and create another LV for Documents with a size of 5. Volume Group. # lvcreate - L 5. G - n Documents storage.
The creation of the Logical Volumes can be confirmed with one of the following commands: lvdisplay .
How to Setup Software RAID for a Simple File Server on Ubuntu. Do you need a file server on the cheap that is easy to setup, “rock solid” reliable with Email Alerting?
So before you clear out a place in your budget for a storage solution, consider a configuration that is licensing free with Linux. With that said, going cheap/free does not mean “throwing caution to the wind”, and to that end, we will note points to be aware of, configurations that should be set in place in addition to using software RAID, to achieve the maximum price to reliability ratio. Image by Filomena Scalise.
About software RAIDAs the name implies, this is a RAID (Redundant Array of Inexpensive Disks) setup that is done completely in software instead of using a dedicated hardware card. The main advantage of such a thing is cost, as this dedicated card is an added premium to the base configuration of the system. The main disadvantages are basically performance and some reliability as such a card usually comes with it’s own RAM+CPU to perform the calculations required for the redundancy math, data caching for increased performance, and the optional backup battery that keeps unwritten operations in the cache until power has been restored in case of a power out.
With a software RAID setup your sacrificing some of the systems CPU performance in order to reduce total system cost, however with todays CPUs the overhead is relatively negligible (especially if your going to mainly dedicate this server to be a “file server”). As far as disk performance go, there is a penalty. The Tom’s Hardware guide “Tom’s goes RAID5” is an oldie but a goody exhaustive article about the subject, which I personally use as reference, however take the benchmarks with a grain of salt as it is talking about windows implementation of software RAID (as with everything else, i’m sure Linux is much better : P). Prerequisites. Patience young one, this is a long read. It is assumed you know what RAID is and what it is used for.
This guide was written using Ubuntu server. Debian based system to work with as well. You will see me use VIM as the editor program, this is just because I’m used to it.
Doing so allowed me to use sda. RAID array, so adjust accordingly to your setup. Depending on the type of RAID you want to create you will need at least two disks on your system and in this guide we are using 6 drives. Choosing the disks that make the array. The first step in avoiding a trap is knowing of it’s existence (Thufir Hawat from Dune). Choosing the disks is a vital step that should not be taken lightly, and you would be wise to capitalize on yours truly’s experience and heed this warning: Do NOT use “consumer grade” drives to create your array, use “server grade” drives!!!!!! Now i know what your thinking, didn’t we say we are going to go on the cheap?
Despite of their attractive price, consumer grade hard drives are not designed to be used in a 2. Trust me, yours truly has tried this for you. At least four consumer grade drives in the 3 servers I have setup like this (due to budget constraints) failed after about 1. While there was no data loss, because the RAID did it’s job well and survived. That may be true, however despite these claims, server grade drives still have a higher level of S. M. A. R. T restrictions and QAing behind them (as can be observed by the fact that they are not released to the market as soon as the consumer drives are), so i still highly recommend that you fork out the extra $$$ for the upgrade.
Choosing the RAID level. Downloadable Free Movie Picture Wallpapers. While I’m not going to go into all of the options available (this is very well documented in the RAID wikipedia entry), I do feel that it is noteworthy to say that you should always opt for at least RAID 6 or even higher (we will be using Linux RAID1. This is because when a disk fails, there is a higher chance of a neighboring disk failure and then you have a “two disk” failure on your hands. Moreover, if your going to use large drives, as larger disks have a higher data density on the platter’s surface, the chance for failure is higher. IMHO disks from 2. T and beyond will always fall into this category, so be aware.
Let’s get cracking. Partitioning disks. While in Linux/GNU, we could use the entire block device for storage needs, we will use partitions because it makes it easier to use disk rescue tools in case the system has gone bonkers. We are using the “fdisk” program here, but if your going to use disks larger then 2.