Linux软raid创建

RAID:

HBA：基于主机的适配器

more

RAID：Redundent Array of Inexpensive Disks 廉价磁盘阵列

Independent       独立磁盘阵列

Level：仅用于标识磁盘组合方式的不同，不能取代数据备份

raid0，raid1，raid5，raid10，raid50，jbod

raid0：提高读写性能，没有容错能力。至少需要两块磁盘 100%

raid1：至少需要两块硬盘，镜像，硬件容错能力，读性能提升，写性能下降 50%

raid4：至少需要三块硬盘，允许一块盘出错，读写性能提升，（n-1）/n

raid5: 至少需要三块硬盘，允许一块盘出错，读写性能提升，（n-1）/n

raid6: 至少需要四块磁盘，允许两块盘出错。读写性能提升，（n-2）/n

raid10：至少需要四块磁盘。允许不同组内个各坏一块盘，读写性能提升，50%

raid01：

jbod：

md，可以组合任何块设备

mdadm，/etc/mdadm.conf

mdadm:模式化的工具

-A  Assemble 装配模式

-C  Create 创建模式

-n #：用于创建RAID设备的个数

-x #: 热备磁盘的个数

-l ：指定RAID级别

-a ：=yes（自动为创建的RAID设备创建设备文件） md mdp part p 如何创建设备文件

-c：指定块的大小，默认为512KB

-F FOLLOW 监控

-S 停止RAID

-D --detail: 显示阵列详细信息

Manage 管理模式专用项

-f：模拟损害

-r：模拟移除设备

-a：模拟添加新设备

watch

-n #:每个#执行一次指定的命令，单位为s

[root@mail ~]# watch -n1 'cat /proc/mdstat'

使用raid0创建一个6G大小的磁盘。

1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120

   [root@mail ~] # fdisk /dev/sdc Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel with disk identifier 0xba68f31c. Changes will remain in memory only, until you decide to write them. After that, of course, the previous content won't be recoverable. Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite) WARNING: DOS-compatible mode is deprecated. It's strongly recommended to switch off the mode ( command 'c' ) and change display units to sectors ( command 'u' ). Command (m for help): n Command action e   extended p   primary partition (1-4) p Partition number (1-4): 1 First cylinder (1-2610, default 1): Using default value 1 Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +6G Command (m for help): n Command action e   extended p   primary partition (1-4) p Partition number (1-4): 2 First cylinder (785-2610, default 785): Using default value 785 Last cylinder, +cylinders or +size{K,M,G} (785-2610, default 2610): +6G Command (m for help): t Partition number (1-4): 1 Hex code ( type L to list codes): fd Changed system type of partition 1 to fd (Linux raid autodetect) Command (m for help): t Partition number (1-4): 2 Hex code ( type L to list codes): fd Changed system type of partition 2 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. [root@mail ~] # mdadm -C /dev/md0 -a yes -l 0 -n 2 /dev/sdc{1,2} mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md0 started. [root@mail ~] # cat /proc/mdstat Personalities : [raid0] md0 : active raid0 sdc2[1] sdc1[0] 12585984 blocks super 1.2 512k chunks unused devices: <none> [root@mail ~] # mdadm -D /dev/md0 /dev/md0 : Version : 1.2 Creation Time : Tue May 10 20:19:43 2016 Raid Level : raid0 Array Size : 12585984 (12.00 GiB 12.89 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Tue May 10 20:19:43 2016 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Chunk Size : 512K Name : mail.saviorsyang.com:0  ( local to host mail.saviorsyang.com) UUID : b5ec8803:366d2e9d:a1ddd0f2:58101d5c Events : 0 Number   Major   Minor   RaidDevice State 0       8       33        0      active sync /dev/sdc1 1       8       34        1      active sync /dev/sdc2 [root@mail ~] # mke2fs -t ext4 /dev/md0 mke2fs 1.43-WIP (20-Jun-2013) Filesystem label= OS type : Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=128 blocks, Stripe width=256 blocks 786864 inodes, 3146496 blocks 157324 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=3225419776 97 block groups 32768 blocks per group, 32768 fragments per group 8112 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done [root@mail ~] # mkdir  /test/md0 [root@mail ~] # mount /dev/md0 /test/md0 [root@mail ~] # mount /dev/mapper/vg_demo-lv_root on / type ext4 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw) /dev/sda1 on /boot type ext4 (rw) /dev/sdb1 on /student type ext4 (rw) /dev/sr0 on /mnt type iso9660 (ro) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) /dev/md0 on /test/md0 type ext4 (rw)

   使用raid1创建一个2G大小的磁盘。

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168

   [root@mail ~] # fdisk /dev/sdc WARNING: DOS-compatible mode is deprecated. It's strongly recommended to switch off the mode ( command 'c' ) and change display units to sectors ( command 'u' ). Command (m for help): n Command action e   extended p   primary partition (1-4) e Partition number (1-4): Value out of range. Partition number (1-4): 3 First cylinder (1569-2610, default 1569): Using default value 1569 Last cylinder, +cylinders or +size{K,M,G} (1569-2610, default 2610): Using default value 2610 Command (m for help): n Command action l   logical (5 or over) p   primary partition (1-4) l First cylinder (1569-2610, default 1569): Using default value 1569 Last cylinder, +cylinders or +size{K,M,G} (1569-2610, default 2610): +2G Command (m for help): n Command action l   logical (5 or over) p   primary partition (1-4) l First cylinder (1831-2610, default 1831): Using default value 1831 Last cylinder, +cylinders or +size{K,M,G} (1831-2610, default 2610): +2G Command (m for help): w The partition table has been altered! Calling ioctl() to re- read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8) Syncing disks. [root@mail ~] # fdisk /dev/sdc WARNING: DOS-compatible mode is deprecated. It's strongly recommended to switch off the mode ( command 'c' ) and change display units to sectors ( command 'u' ). Command (m for help): t Partition number (1-6): 5 Hex code ( type L to list codes): fd Changed system type of partition 5 to fd (Linux raid autodetect) Command (m for help): t Partition number (1-6): 6 Hex code ( type L to list codes): fd Changed system type of partition 6 to fd (Linux raid autodetect) Command (m for help): w The partition table has been altered! Calling ioctl() to re- read partition table. WARNING: Re-reading the partition table failed with error 16: Device or resource busy. The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8) Syncing disks. [root@mail ~] # partx /dev/sdc # 1:        63- 12594959 ( 12594897 sectors,   6448 MB) # 2:  12594960- 25189919 ( 12594960 sectors,   6448 MB) # 3:  25189920- 41929649 ( 16739730 sectors,   8570 MB) # 4:         0-       -1 (        0 sectors,      0 MB) # 5:  25189983- 29398949 (  4208967 sectors,   2154 MB) # 6:  29399013- 33607979 (  4208967 sectors,   2154 MB) [root@mail ~] # cat /proc/partitions major minor #blocks  name 8       32   20971520 sdc 8       33    6297448 sdc1 8       34    6297480 sdc2 8       35         31 sdc3 8       37    2104483 sdc5 8       38    2104483 sdc6 8        0   52428800 sda 8        1     512000 sda1 8        2   51915776 sda2 8       16  524288000 sdb 8       17  524281243 sdb1 8       48   20971520 sdd 11        0    3763200 sr0 252        0   47816704 dm-0 252        1    4096000 dm-1 9        0   12585984 md0 [root@mail ~] # mdadm -C /dev/md1 -a yes -l 1 -n 2 /dev/sdc{5,6} mdadm: Note: this array has metadata at the start and may not be suitable as a boot device.  If you plan to store '/boot' on this device please ensure that your boot-loader understands md /v1 .x metadata, or use --metadata=0.90 Continue creating array? yes mdadm: Defaulting to version 1.2 metadata mdadm: array /dev/md1 started. [root@mail ~] # cat /proc/mdstat Personalities : [raid0] [raid1] md1 : active raid1 sdc6[1] sdc5[0] 2102400 blocks super 1.2 [2 /2 ] [UU] [=================>...]  resync = 85.5% (1800064 /2102400 ) finish=0.0min speed=200007K /sec md0 : active raid0 sdc2[1] sdc1[0] 12585984 blocks super 1.2 512k chunks unused devices: <none> [root@mail ~] # cat /proc/mdstat Personalities : [raid0] [raid1] md1 : active raid1 sdc6[1] sdc5[0] 2102400 blocks super 1.2 [2 /2 ] [UU] md0 : active raid0 sdc2[1] sdc1[0] 12585984 blocks super 1.2 512k chunks unused devices: <none> [root@mail ~] # [root@mail ~] # mke2fs -t ext4 /dev/md1 mke2fs 1.43-WIP (20-Jun-2013) Filesystem label= OS type : Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 131648 inodes, 525600 blocks 26280 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=541065216 17 block groups 32768 blocks per group, 32768 fragments per group 7744 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912 Allocating group tables: done Writing inode tables: done Creating journal (16384 blocks): done Writing superblocks and filesystem accounting information: done [root@mail ~] # mkdir -pv /test/md1 [root@mail ~] # mount /dev/md1 /test/md1 [root@mail ~] # mount /dev/mapper/vg_demo-lv_root on / type ext4 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw) /dev/sda1 on /boot type ext4 (rw) /dev/sdb1 on /student type ext4 (rw) /dev/sr0 on /mnt type iso9660 (ro) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) /dev/md1 on /test/md1 type ext4 (rw)