Difference between revisions of "linux software raid 5 quick guide"
From thelinuxwiki
| Line 5: | Line 5: | ||
All drives same size | All drives same size | ||
All space used on all drives | All space used on all drives | ||
| − | + | devices to be used in this example: sdb sdc sdd | |
| Line 19: | Line 19: | ||
== prepare disks == | == prepare disks == | ||
| + | '''check existing partition tables''' | ||
| + | |||
| + | this command will dump the partitions for all three drives | ||
# '''fdisk -l /dev/sd[bcd]''' | # '''fdisk -l /dev/sd[bcd]''' | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | create three raid partions of | + | |
| + | '''create three raid partions''' | ||
| + | |||
| + | assuming they don't already exist... | ||
| + | |||
| + | linux # '''fdisk /dev/sdb''' | ||
| + | <br>The device presents a logical sector size that is smaller than | ||
| + | the physical sector size. Aligning to a physical sector (or optimal | ||
| + | I/O) size boundary is recommended, or performance may be impacted. | ||
| + | Welcome to fdisk (util-linux 2.22.2). | ||
| + | <br>Changes will remain in memory only, until you decide to write them. | ||
| + | Be careful before using the write command. | ||
| + | <br><br>Command (m for help): '''n''' | ||
| + | Partition type: | ||
| + | p primary (0 primary, 0 extended, 4 free) | ||
| + | e extended | ||
| + | Select (default p): | ||
| + | Using default response '''p''' | ||
| + | Partition number (1-4, default 1): | ||
| + | Using default value 1 | ||
| + | First sector (2048-1953525167, default 2048): | ||
| + | Using default value 2048 | ||
| + | Last sector, +sectors or +size{K,M,G} (2048-1953525167, default 1953525167): | ||
| + | Using default value 1953525167 | ||
| + | Partition 1 of type Linux and of size 931.5 GiB is set | ||
| + | <br>Command (m for help): '''t''' | ||
| + | Selected partition 1 | ||
| + | Hex code (type L to list codes): '''fd''' | ||
| + | Changed system type of partition 1 to fd (Linux raid autodetect) | ||
| + | <br>Command (m for help): w | ||
| + | The partition table has been altered! | ||
| + | <br>Calling ioctl() to re-read partition table. | ||
| + | Syncing disks. | ||
| + | |||
| + | |||
Revision as of 19:28, 30 March 2014
Here will create a raid 5 setup with three drives for redundant storage using mdadm (not raidtools). This example does not include putting your O.S. root partion on the raid device. It is only for a volume to be mounted by Linux which boots off of another device.
Number of drives: 3 Number of spare drives: 0 All drives same size All space used on all drives devices to be used in this example: sdb sdc sdd
Contents |
kernel config
Check for support If your system has RAID support, you should have a file called /proc/mdstat. If you do not have that file, maybe your kernel does not have RAID support. For more info on configuring your linux kernel for software raid, go here
install mdadm
prepare disks
check existing partition tables
this command will dump the partitions for all three drives
# fdisk -l /dev/sd[bcd]
create three raid partions
assuming they don't already exist...
linux # fdisk /dev/sdb
The device presents a logical sector size that is smaller than the physical sector size. Aligning to a physical sector (or optimal I/O) size boundary is recommended, or performance may be impacted. Welcome to fdisk (util-linux 2.22.2).
Changes will remain in memory only, until you decide to write them. Be careful before using the write command.
Command (m for help): n Partition type: p primary (0 primary, 0 extended, 4 free) e extended Select (default p): Using default response p Partition number (1-4, default 1): Using default value 1 First sector (2048-1953525167, default 2048): Using default value 2048 Last sector, +sectors or +size{K,M,G} (2048-1953525167, default 1953525167): Using default value 1953525167 Partition 1 of type Linux and of size 931.5 GiB is set
Command (m for help): t Selected partition 1 Hex code (type L to list codes): fd Changed system type of partition 1 to fd (Linux raid autodetect)
Command (m for help): w The partition table has been altered!
Calling ioctl() to re-read partition table. Syncing disks.
Creating an array
Links
this guide is recommended by the linux kernel help... [Software RAID HOWTO]
