Differences

This shows you the differences between two versions of the page.

--- raid:mdadm:lvm_on_raid [2021/10/01 11:38] – created peter
+++ raid:mdadm:lvm_on_raid [2021/10/01 17:18] (current) – peter
@@ Line 5: / Line 5: @@
   * This Volume Group can be split into Logical Volumes; in essence different Partitions.
   * LVM provides the ability to resize these Logical Volumes very easily.
-  * LVM is not a replacement for RAID, as it only supports mirroring or stripe.
+  * LVM is not a replacement for RAID, as LVM does not provide any options for redundancy or parity that RAID provides.
-    * Using LVM for resilience without RAID would result in twice as much storage being needed; a waste.
     * Therefore it is best to be have LVM in conjunction with RAID.
+<code>
+|--------------------------------------------------------------------------------------------|
+|LVM Logical Volumes | / | /var | /usr | /home | /mnt                                        |
+|--------------------------------------------------------------------------------------------|
+|LVM Volume Group    |                            /dev/VolGroupArray                         |
+|--------------------------------------------------------------------------------------------|
+|RAID Arrays         |                   /dev/md0                     |      /dev/md1        |
+|--------------------------------------------------------------------------------------------|
+|Physical Partitions | /dev/sda1 | /dev/sda2 | /dev/sdb1 | /dev/sdb2 | /dev/sdc1 | /dev/sdc2 |
+|--------------------------------------------------------------------------------------------|
+|Devices             |         /dev/sda      |         /dev/sdb      |         /dev/sdc      |
+|--------------------------------------------------------------------------------------------|
+|Hard Drives         |          Drive 1      |          Drive 2      |          Drive 3      |
+|--------------------------------------------------------------------------------------------|
+</code>
 <WRAP info>
@@ Line 43: / Line 58: @@
   * Enter an **e** for an extended partition.
   * Enter a **p** for a primary partition (1-4).
-  * Enter a **1* for primary partition number 1.
+  * Enter a **1** for primary partition number 1.
   * Accept the default sizes.
@@ Line 54: / Line 69: @@
 ===== Wipe everything =====
 <code bash>
@@ Line 65: / Line 78: @@
 ----
 ===== Create the RAID Array =====
@@ Line 263: / Line 275: @@
                      629126396     32840 629093556   1% /mnt/data
 </code>
+<WRAP info>
+**NOTE:**  To auto mount, add following to /etc/fstab:
+<file bash /etc/fstab>
+/dev/myVolumeGroup1-myDataVolume /mnt/data       ext4     defaults        1       2
+</file>
+</WRAP>
 ----
@@ Line 283: / Line 305: @@
 </WRAP>
+If the system has sufficient RAM the size of the software RAID MD cache can be increased:
+<code bash>
+echo 8192 > /sys/block/md0/md/stripe_cache_size
+</code>
 ----