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3.2. 멀티패스 장치 생성 시 로컬 디스크 무시

Some machines have local SCSI cards for their internal disks. DM Multipath is not recommended for these devices. If you set the find_multipaths configuration parameter to yes, you should not have to blacklist these devices. For information on the find_multipaths configuration parameter, see 4.3절. “설정 파일 기본값 ”.
If you do not set the find_multipaths configuration parameter to yes, can use the following procedure to modify the multipath configuration file to ignore the local disks when configuring multipath.
  1. 어떤 디스크가 내부 디스크인지를 지정하고 블랙리스트에 이를 표시합니다.
    In this example, /dev/sda is the internal disk. Note that as originally configured in the default multipath configuration file, executing the multipath -v2 command shows the local disk, /dev/sda, in the multipath map.
    This examples specifies the -d option of the multipath command to indicate that this is a dry run that will not create the multipath devices. For further information on the multipath command output, see 5.7절. “Multipath Command Output”. 
    # multipath -v2 -d
: SIBM-ESXSST336732LC____F3ET0EP0Q000072428BX1 undef WINSYS,SF2372
size=33 GB features="0" hwhandler="0" wp=undef
`-+- policy='round-robin 0' prio=1 status=undef
  |- 0:0:0:0 sda 8:0  [--------- 

: 3600a0b80001327d80000006d43621677 undef WINSYS,SF2372
size=12G features='0' hwhandler='0' wp=undef
`-+- policy='round-robin 0' prio=1 status=undef
  |- 2:0:0:0 sdb 8:16  undef ready  running
  `- 3:0:0:0 sdf 8:80 undef ready  running

: 3600a0b80001327510000009a436215ec undef WINSYS,SF2372
size=12G features='0' hwhandler='0' wp=undef
`-+- policy='round-robin 0' prio=1 status=undef
  |- 2:0:0:1 sdc 8:32 undef ready  running
  `- 3:0:0:1 sdg 8:96 undef ready  running

: 3600a0b80001327d800000070436216b3 undef WINSYS,SF2372
size=12G features='0' hwhandler='0' wp=undef
`-+- policy='round-robin 0' prio=1 status=undef
  |- 2:0:0:2 sdd 8:48 undef ready  running
  `- 3:0:0:2 sdg 8:112 undef ready  running

: 3600a0b80001327510000009b4362163e undef WINSYS,SF2372
size=12G features='0' hwhandler='0' wp=undef
`-+- policy='round-robin 0' prio=1 status=undef
  |- 2:0:0:3 sdd 8:64 undef ready  running
  `- 3:0:0:3 sdg 8:128 undef ready  running
  2. In order to prevent the device mapper from mapping /dev/sda in its multipath maps, edit the blacklist section of the /etc/multipath.conf file to include this device. Although you could blacklist the sda device using a devnode type, that would not be a safe procedure since /dev/sda is not guaranteed to be the same on reboot. To blacklist individual devices, you can blacklist using the WWID of that device.
    multipath -v2 명령의 출력 결과에서 /dev/sda 장치의 WWID는 SIBM-ESXSST336732LC____F3ET0EP0Q000072428BX1입니다. 이러한 장치를 블랙리스트하려면, /etc/multipath.conf 파일에 다음을 포함시킵니다. 
    blacklist {
      wwid SIBM-ESXSST336732LC____F3ET0EP0Q000072428BX1
}
  3. /etc/multipath.conf 파일을 업데이트한 후, 파일을 다시 불러오기 위해 수동으로 multipathd 데몬을 작동시켜야 합니다. 다음의 명령은 업데이트된 /etc/multipath.conf 파일을 다시 불러오기합니다. 
    # systemctl reload multipathd.service