|
RAID, the Redundant Array of Inexpensive Disks, provides several features that are valuable for servers. RAID can provide speed enhancements for your server and RAID can provide redundancy or it can provide both. There are several levels of RAID that you may use, these levels map to the tasks that you want RAID to perform. This series of tutorials will take you through creating software RAID for levels 0,1 and 5. Create RAID Partitions with fdisk
You must become familiar with fdisk as this is the tool you will use to create partitions. Be sure you practice these skills on a test server before you work on a production server. You will need to install the mdadm program to create software RAID. sudo apt-get install mdadm
Create 4 raid devices with fdisk. Be sure that you edit the correct drive so that you do not damage the drive you have your operating system on.
# fdisk /dev/sdb
Command (m for help): p
Device Boot Start End Blocks Id System
/dev/sdb1 1 48632 390636508+ 83 Linux
Print the partition entries - see what is there before you begin the process. It is always a good idea to verify that what you are about to destroy is what you want to destroy. No doubt about it, if you partition it all information will be gone.
Command (m for help): n
n will create a new partition.
Command action
e extended
p primary partition (1-4)
e
An extended partition is created so that logical partitions may be created out of the extended partition. You can only have 3 primary partitions and then an extended partition.
Partition number (1-4): 4
First cylinder (48633-60801, default 48633):
Using default value 48633
Last cylinder or +size or +sizeM or +sizeK (48633-60801, default 60801):
Using default value 60801
Command (m for help): p It is always a good idea to verify the work you have done by viewing it with p. Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xe7ee79f4
Device Boot Start End Blocks Id System
/dev/sdb1 1 48632 390636508+ 83 Linux
/dev/sdb4 48633 60801 97747492+ 5 Extended
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l The l is a logical partition that is created from the large extended partition. Note that the drive sizes that are created below are only for illustration purposes. Your RAID partitions should be on separate drives and they should larger. The small drives are just to illustrate the process. First cylinder (48633-60801, default 48633):
Using default value 48633
Last cylinder or +size or +sizeM or +sizeK (48633-60801, default 60801): +500M
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l
First cylinder (48695-60801, default 48695):
Using default value 48695
Last cylinder or +size or +sizeM or +sizeK (48695-60801, default 60801): +500M
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l
First cylinder (48757-60801, default 48757):
Using default value 48757
Last cylinder or +size or +sizeM or +sizeK (48757-60801, default 60801): +500M
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l
First cylinder (48819-60801, default 48819):
Using default value 48819
Last cylinder or +size or +sizeM or +sizeK (48819-60801, default 60801): +500M
Command (m for help): p
Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xe7ee79f4
Device Boot Start End Blocks Id System
/dev/sdb1 1 48632 390636508+ 83 Linux
/dev/sdb4 48633 60801 97747492+ 5 Extended
/dev/sdb5 48633 48694 497983+ 83 Linux
/dev/sdb6 48695 48756 497983+ 83 Linux
/dev/sdb7 48757 48818 497983+ 83 Linux
/dev/sdb8 48819 48880 497983+ 83 Linux Here you can see 4 small partitions are created. These are not RAID available as the type is 83 which is the ext3 partitions. You will need to cahnge the type. Type can be changed by using the t option. Command (m for help): t
Partition number (1-8): 5
Hex code (type L to list codes): L
The L option will list the possibilities for types on partitions.
0 Empty 1e Hidden W95 FAT1 80 Old Minix be Solaris boot
1 FAT12 24 NEC DOS 81 Minix / old Lin bf Solaris
2 XENIX root 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
3 XENIX usr 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
4 FAT16 <32M 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
5 Extended 41 PPC PReP Boot 85 Linux extended c7 Syrinx
6 FAT16 42 SFS 86 NTFS volume set da Non-FS data
7 HPFS/NTFS 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
8 AIX 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
9 AIX bootable 4f QNX4.x 3rd part 8e Linux LVM df BootIt
a OS/2 Boot Manag 50 OnTrack DM 93 Amoeba e1 DOS access
b W95 FAT32 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
c W95 FAT32 (LBA) 52 CP/M 9f BSD/OS e4 SpeedStor
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
f W95 Ext'd (LBA) 54 OnTrackDM6 a5 FreeBSD ee EFI GPT
10 OPUS 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
11 Hidden FAT12 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
12 Compaq diagnost 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
14 Hidden FAT16 <3 61 SpeedStor a9 NetBSD f4 SpeedStor
16 Hidden FAT16 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fd Linux raid auto
18 AST SmartSleep 65 Novell Netware b8 BSDI swap fe LANstep
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid ff BBT
1c Hidden W95 FAT3 75 PC/IX
Hex code (type L to list codes): fd
Changed system type of partition 5 to fd (Linux raid autodetect)
The type you must use for creating RAID is fd.
Command (m for help): t
Partition number (1-8): 6
Hex code (type L to list codes): fd
Changed system type of partition 6 to fd (Linux raid autodetect)
Command (m for help): t
Partition number (1-8): 7
Hex code (type L to list codes): fd
Changed system type of partition 7 to fd (Linux raid autodetect)
Command (m for help): t
Partition number (1-8): 8
Hex code (type L to list codes): fd
Changed system type of partition 8 to fd (Linux raid autodetect)
Command (m for help): p
Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xe7ee79f4
Device Boot Start End Blocks Id System
/dev/sdb1 1 48632 390636508+ 83 Linux
/dev/sdb4 48633 60801 97747492+ 5 Extended
/dev/sdb5 48633 48694 497983+ fd Linux raid autodetect
/dev/sdb6 48695 48756 497983+ fd Linux raid autodetect
/dev/sdb7 48757 48818 497983+ fd Linux raid autodetect
/dev/sdb8 48819 48880 497983+ fd Linux raid autodetect
Note that the partitions types have now been changed. Now they are RAID aware.
Command (m for help): w
The partition table has been altered! Write the information to disk
Nothing has changed on the drive until you use the w option, then all the information that you have created will be written to the drive. When you write to disk using the w option it will be forever changed!!!!!!! So be careful you have a backup. Once you use the w option you will see the disk syncing. You may have to restart to get both partitions setup.
Calling ioctl() to re-read partition table.
Syncing disks.
RAID partitions have now been created. You will need to verify that the system recognizes those partitions with partprobe or restart.
# partprobe
Your partitions are now ready to be used by RAID. The next step is to decide what level of RAID you want to use for your Ubuntu server.
Copyright CyberMontana Inc. and BeginLinux.com All rights reserved. Cannot be reproduced without written permission. Box 1262 Trout Creek, MT 59874
|
