[Linux] LINUX RAID1 구축

 

- 이번에는 raid1(mirrorring)을 구축해 보겠다.

- 기타등등은 raid0 구성하는 것과 거의 같으므로 생략한다(필자 블로그에서 raid0 구축방법 찾아보길 바란다)

- raid1은 아시다 싶이 미러링이다. 즉 2개의 디스크에 똑같은 내용을 쓴다.. 같은 내용을 2개의 디스크에 써야함으로 write 속도는 그닥 빠르지 않다. 그러나 read 속도는 빠르다. 2개의 디스크에서 읽어 올 수 있기 때문이다.

- 구축은 sdd1 과 sde1 을 만들고 mdadm 으로 구축하면 되겠다.

1) sdd1 과 sde1 을 파일시스템으로 만들고  파일시스템 유형은 Linux raid auto 로 준다.

[root@localhost ~]# fdisk /dev/sdd
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. 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)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-204, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-204, default 204):
Using default value 204

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.
[root@localhost ~]# fdisk /dev/sde
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. 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)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-204, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-204, default 204):
Using default value 204

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.

2) 장치명을 주어야 한다. md1 을 찾아보고(md0 은 raid0 을 만드는데 쓰였다.) 없으면 mknod 명령으로 만들어준다.

[root@localhost ~]# ls -al /dev/md?
brw-r-----  1 root disk 9, 0  3??26 00:24 /dev/md0   <--- raid0 용
[root@localhost ~]# mknod /dev/md1 b 9 1
[root@localhost ~]# ls -al /dev/md?
brw-r-----  1 root disk 9, 0  3??26 00:24 /dev/md0
brw-r--r--  1 root root 9, 1  3??26 01:20 /dev/md1  <--- raid1 용

3) mdadm 명령으로 radi1 구성한다.

[root@localhost ~]# mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdd1 /dev/sde1
mdadm: array /dev/md1 started.
[root@localhost ~]# mdadm --detail --scan
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=6780793c:b171ede2:d0a38176:a24fbe36
   devices=/dev/sdd1,/dev/sde1   <--- 방금 구성한 raid1
ARRAY /dev/md0 level=raid0 num-devices=2 UUID=80ce56ed:8a0ca06d:d96d03b6:77ae5f91
   devices=/dev/sdb1,/dev/sdc1   <--- 이전의 raid0
[root@localhost ~]#

4) md1 을 파일시스템 만들고 /raid1로 마운트한다.

[root@localhost ~]# mkfs.ext3 /dev/md1
mke2fs 1.37 (21-Mar-2005)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
52208 inodes, 208768 blocks
10438 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67371008
26 block groups
8192 blocks per group, 8192 fragments per group
2008 inodes per group
Superblock backups stored on blocks:
        8193, 24577, 40961, 57345, 73729, 204801

Writing inode tables: done                           
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 31 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
[root@localhost ~]# mkdir /raid1
[root@localhost ~]# mount /dev/md1 /raid1
[root@localhost ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             6.7G  2.4G  4.0G  38% /
/dev/shm              147M     0  147M   0% /dev/shm
/dev/md0              395M   11M  365M   3% /raid0
/dev/md1              198M  5.8M  182M   4% /raid1
[root@localhost ~]#

5) /etc/fstab 에 추가 하면 끝

[root@localhost ~]# vi /etc/fstab

# This file is edited by fstab-sync - see 'man fstab-sync' for details
LABEL=/                 /                       ext3    defaults        1 1
/dev/devpts             /dev/pts                devpts  gid=5,mode=620  0 0
/dev/shm                /dev/shm                tmpfs   defaults        0 0
/dev/proc               /proc                   proc    defaults        0 0
/dev/sys                /sys                    sysfs   defaults        0 0
/dev/md0                /raid0                  ext3    defaults        1 1
/dev/md1                /raid1                  ext3    defaults        1 1    <--- 추가된것
LABEL=SWAP-sda2         swap                    swap    defaults        0 0
/dev/fd0                /media/floppy           auto    pamconsole,exec,noauto,managed 0 0
/dev/hdc                /media/cdrecorder       auto    pamconsole,exec,noauto,managed 0 0