테스트 사이트 - 개발 중인 베타 버전입니다

mdadm multipath

· 13년 전 · 564
 
 
/dev/xvda8            1583        1595      104391   83  Linux
/dev/xvda9            1596        1608      104391   83  Linux
/dev/xvda10           1609        1621      104391   83  Linux
 
 
 
멀티패스는 하드웨어 고장시 다른 경로로 데이터를 계속 주고 받을 수 있도록 하기 위함임.
 
 
/etc/mdadm.conf
 
DEVICE /dev/xvda[89],/dev/xvda10
ARRAY /dev/md1 devices=/dev/xvda8,/dev/xvda9,/dev/xvda10
 
[root@www ~]# mdadm -C /dev/md1 --level=multipath --raid-devices=3 /dev/xvda8 /dev/xvda9 /dev/xvda10
mdadm: array /dev/md1 started.
 
 
multipath 지정하면 raid0 으로 된다.
 
[root@www ~]# cat /proc/mdstat 
Personalities : [raid0] [multipath] 
md1 : active multipath xvda10[0] xvda9[1] xvda8[2]
      104320 blocks [3/3] [UUU]
 
[root@www ~]# mdadm --detail /dev/md1
/dev/md1:
        Version : 0.90
  Creation Time : Wed Sep 14 16:03:47 2011
     Raid Level : multipath
     Array Size : 104320 (101.89 MiB 106.82 MB)
   Raid Devices : 3
  Total Devices : 3
Preferred Minor : 1
    Persistence : Superblock is persistent
 
    Update Time : Wed Sep 14 16:03:47 2011
          State : clean
 Active Devices : 3
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 0
 
           UUID : 6a4418e4:1171167a:645e0ce3:753772a6
         Events : 0.3
 
    Number   Major   Minor   RaidDevice State
       0     202       10        0      active sync   /dev/xvda10
       1     202        9        1      active sync   /dev/xvda9
       2     202        8        2      active sync   /dev/xvda8
 
 
 
/dev/xvda8 이 문제가 있을 경우 어떻게 되는지 확인해 보자.
 
아래 옵션을 사용한다.
 
-f, --fail
-r, --remove
-a, --add
 
 
다른점은 공간이 하드 1개의 공간밖에 안된다는것이다.
멀티패스의 장점이 있지만, 3개의 공간 문제는 있다. 그러나 데이터 안정성을 위해서는
괜찮은 것 같다.
/dev/md1               99M  5.6M   89M   6% /data1
 
 
/dev/xvda8 을 fail로 만든다.
[root@www ~]# mdadm /dev/md1 -f /dev/xvda8
mdadm: set /dev/xvda8 faulty in /dev/md1
 
 
/data1 파일쓰기가 가능하다.
 
[root@www ~]# cd /data1
[root@www data1]# ls
lost+found
[root@www data1]# touch 1
[root@www data1]# ls -al
total 21
drwxr-xr-x  3 root root  1024 Sep 14 16:10 .
drwxr-xr-x 24 root root  4096 Sep 14 16:08 ..
-rw-r--r--  1 root root     0 Sep 14 16:10 1
drwx------  2 root root 12288 Sep 14 16:08 lost+found
 
 
문제있는 하드를 제거
[root@www data1]# mdadm /dev/md1 -r /dev/xvda8
mdadm: hot removed /dev/xvda8
 
다시 하드를 리스트에 추가
[root@www data1]# mdadm /dev/md1 -a /dev/xvda8
mdadm: re-added /dev/xvda8
 
 
시스템 메세지에 나타난 부분
 
Sep 14 16:03:47 www kernel: md1: WARNING: xvda9 appears to be on the same physical disk as xvda8. True
Sep 14 16:03:47 www kernel:      protection against single-disk failure might be compromised.
Sep 14 16:03:47 www kernel: md: bind<xvda9>
Sep 14 16:03:47 www kernel: md1: WARNING: xvda10 appears to be on the same physical disk as xvda9. True
Sep 14 16:03:47 www kernel:      protection against single-disk failure might be compromised.
Sep 14 16:03:47 www kernel: md: bind<xvda10>
Sep 14 16:03:47 www kernel: md: multipath personality registered for level -4
Sep 14 16:03:47 www kernel: multipath: array md1 active with 3 out of 3 IO paths
Sep 14 16:09:08 www kernel: kjournald starting.  Commit interval 5 seconds
Sep 14 16:09:08 www kernel: EXT3 FS on md1, internal journal
Sep 14 16:09:08 www kernel: EXT3-fs: mounted filesystem with ordered data mode.
Sep 14 16:10:10 www kernel: multipath: IO failure on xvda8, disabling IO path.
Sep 14 16:10:10 www kernel:     Operation continuing on 2 IO paths.
Sep 14 16:10:10 www kernel: MULTIPATH conf printout:
Sep 14 16:10:10 www kernel:  --- wd:2 rd:3
Sep 14 16:10:10 www kernel:  disk0, o:1, dev:xvda10
Sep 14 16:10:10 www kernel:  disk1, o:1, dev:xvda9
Sep 14 16:10:10 www kernel:  disk2, o:0, dev:xvda8
Sep 14 16:10:10 www kernel: MULTIPATH conf printout:
Sep 14 16:10:10 www kernel:  --- wd:2 rd:3
Sep 14 16:10:10 www kernel:  disk0, o:1, dev:xvda10
Sep 14 16:10:10 www kernel:  disk1, o:1, dev:xvda9
Sep 14 16:11:19 www kernel: md: unbind<xvda8>
Sep 14 16:11:19 www kernel: md: export_rdev(xvda8)
Sep 14 16:13:28 www kernel: md1: WARNING: xvda8 appears to be on the same physical disk as xvda10. True
Sep 14 16:13:28 www kernel:      protection against single-disk failure might be compromised.
Sep 14 16:13:28 www kernel: md: bind<xvda8>

댓글 작성

댓글을 작성하시려면 로그인이 필요합니다.

로그인하기

게시글 목록

번호 제목
12413
12412
12411
12410
12407
12406
12405
12404
12403
12402
12401
12400
12399
12398
12397
12396
12395
12394
12393
12392
12391
12390
12389
12388
12387