Software RAID on FC6 - Revision history

J: /* LVM */

2014-03-01T19:39:25Z

‎LVM

J: /* Add a Line to fstab */

2014-03-01T19:23:11Z

‎Add a Line to fstab

J: /* LVM */

2014-03-01T18:53:33Z

‎LVM

J: /* LVM */

2014-03-01T18:51:55Z

‎LVM

J: /* Create Filesystem on Array */

2014-03-01T18:50:00Z

‎Create Filesystem on Array

J: /* Set Array to be Available On Boot */

2014-03-01T17:25:19Z

‎Set Array to be Available On Boot

J: /* Formatting the Drives Properly */

2014-03-01T17:20:00Z

‎Formatting the Drives Properly

J: /* Create Filesystem on Array */

2014-03-01T17:17:33Z

‎Create Filesystem on Array

J: /* Formatting the Drives Properly */

2014-03-01T17:14:44Z

‎Formatting the Drives Properly

J at 05:22, 30 August 2008

2008-08-30T05:22:50Z

← Older revision		Revision as of 19:39, 1 March 2014
Line 141:		Line 141:

	'''For the remainder of this page, you will see /dev/md0 referenced. You should use your LV path(s) instead wherever we are accessing data (mounting drives). Use md0 only when we're managing the raid array (adding / removing disks, checking rebuild status, etc).'''		'''For the remainder of this page, you will see /dev/md0 referenced. You should use your LV path(s) instead wherever we are accessing data (mounting drives). Use md0 only when we're managing the raid array (adding / removing disks, checking rebuild status, etc).'''
		+
		+	[http://www.howtogeek.com/howto/40702/how-to-manage-and-use-lvm-logical-volume-management-in-ubuntu/ Here] is a pretty good LVM reference.

	===Set up mdadm.conf===		===Set up mdadm.conf===

@@ Line 185: / Line 185: @@
 <pre>
-/dev/md0                /store                   ext3    defaults        0 0
+/dev/md0                /store                   ext4    defaults        0 0
 </pre>
 Substitute your mdadm device for "/dev/md0", where you want it mounted for "/store", and the file system you chose for "ext3".  The rest should stay the same unless you know what you're doing.
 That's it! Should work.

@@ Line 140: / Line 140: @@
 </pre>
-'''For the remainder of this page, you will see /dev/md0 referenced.  You should use your LV path(s) instead wherever you see that.'''
+'''For the remainder of this page, you will see /dev/md0 referenced.  You should use your LV path(s) instead wherever we are accessing data (mounting drives).  Use md0 only when we're managing the raid array (adding / removing disks, checking rebuild status, etc).'''
 ===Set up mdadm.conf===

@@ Line 139: / Line 139: @@
 # mkfs -t ext4 /dev/vgsomename/lvsomename
 </pre>
 ===Set up mdadm.conf===

@@ Line 91: / Line 91: @@
 ===Create Filesystem on Array===
 <pre>
-#/sbin/mkfs -t ext3 /dev/md0
+#/sbin/mkfs -t ext4 /dev/md0
 </pre>
 ===Set up mdadm.conf===

@@ Line 82: / Line 82: @@
 ===Set Array to be Available On Boot===
-In order to make the array available on boot, the "FD" flag must be set on each partition. FC will detect the "FD" flags and initialize the array automatically. To set the "FD" flag simply run:
+For older systems, in order to make the array available on boot, the "FD" flag must be set on each partition. Mdadm would detect the "FD" flags and initialize the array automatically. To set the "FD" flag simply run:
 <pre>
 #/sbin/parted /dev/sda set 1 raid on
 </pre>
 on each of your devices - substitute /dev/sda with your device.
 ===Create Filesystem on Array===

@@ Line 57: / Line 57: @@
 Sorry, haven't gotten here yet!  Google for depmod and your distribution name.
 ===Formatting the Drives Properly===
-Now this is where things get interesting, but not too complex. In order to make software RAID work, we need to make partitions on the devices before the array is built.  You can use the bare drive block devices, but using partitions has some benefits and avoids some scary warnings. So, use [http://man-wiki.net/index.php/8:parted parted] if you like command lines or [http://gparted.sourceforge.net/ gpared] if you like GUIs to create a partition on each device. I believe you can use any filesystem you like, however I have only used ext3.  Make sure you format the devices in the file system that you want to use on the array.  All devices in the array should be the same filesystem.  See the [http://man-wiki.net/index.php/8:parted man page for parted] or the homepage for [http://gparted.sourceforge.net/ gpared] for instructions on formatting drives.
+Now this is where things get interesting, but not too complex. In order to make software RAID work, we need to make partitions on the devices before the array is built.  You can use the bare drive block devices, but using partitions has some benefits and avoids some scary warnings. So, use [http://man-wiki.net/index.php/8:parted parted] if you like command lines or [http://gparted.sourceforge.net/ gpared] if you like GUIs to create a partition on each device. You do not need to format the partitions to any file system.  Blank partitions is what you need - the process of creating blank partitions is practically instantaneous.
-For those of you who have dealt with hardware RAID, this is a very strange thing to do.  Usually, you would have simply created an array of the blank drives, but software RAID with mdadm doesn't see drives, only partitions.
+If you want to create partitions that use the whole drive, and your drives are larger than 2TB you can do something like this to set your drive up to use GPT and create an empty partition (substituting "sda" for your drive, of course):
-−
 If you want to create partitions that use the whole drive, and your drives are larger than 2TB you can do this to set your drive up to use GPT and create an empty partition:
 <pre>
 # parted -s -a optimal /dev/sda mklabel gpt -- mkpart primary 1 -1

@@ Line 94: / Line 94: @@
 #/sbin/mkfs -t ext3 /dev/md0
 </pre>
-Should take care of that.  Substitute ext3 for whatever filesystem you want.  Make sure it matches what you formatted the drives to in the beginning, or this whole thing might not work.
+Should take care of that.  Substitute ext3 for whatever filesystem you want.
 ===Set up mdadm.conf===

@@ Line 4: / Line 4: @@
 {|-
 | valign="top" |
-The document details the steps I had to take to build a software RAID array using mdadm.  The document was originally written for Fedora Core 6, but has been updated to cover a wider range of distributions. The process was very tedious and I could not find any one document that gave me enough information to complete the project. I will include all parts of the process from selecting hardware and cabling to building the array and setting it to mount automatically. I will assume the reader has a good knowledge of computer hardware and knows at least a little about SCSI and how to run Linux operating systems. For more information about RAID levels see [http://en.wikipedia.org/wiki/Standard_RAID_levels this].  Feel free to e-mail me with specific questions (if you're creative enough to find my address).
+The document details the steps I had to take to build a software RAID array using mdadm.  The document was originally written for Fedora Core 6, but has been updated to cover a wider range of distributions. The process was very tedious and I could not find any one document that gave me enough information to complete the project. I will include all parts of the process from selecting hardware and cabling to building the array and setting it to mount automatically. I will assume the reader has a good knowledge of computer hardware and knows at least a little about SCSI and how to run Linux operating systems. For more information about RAID levels see [http://en.wikipedia.org/wiki/Standard_RAID_levels this].  Feel free to [[Special:Emailuser/J|e-mail me]] with specific questions.
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