multipath

这里我们先通过两个地址连接了iscsi 存储，通过两个目标IP，连接同一个target，在本地生成了sda 和sdb，sda和sdb是拥有同样的wwid的

[root@node1 ~]# /usr/lib/udev/scsi_id -u -g /dev/sda
360014059c2719519e0f4445afbb30030
[root@node1 ~]#
[root@node1 ~]# /usr/lib/udev/scsi_id -u -g /dev/sdb
360014059c2719519e0f4445afbb30030

Install multipath and load module

Install multipath

yum install device-mapper-multipath -y

load module

modprobe dm_multipath

check the module is load already

lsmod|grep multipath

set load mudule automatic.

echo 'modprobe dm_multipath' >> /etc/rc.d/rc.local
chmod +x /etc/rc.d/rc.local

check multipath configuration file

multipath

create a multipath file

cp /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf /etc/

start and enable multipathd

systemctl restart multipathd
systemctl is-active multipathd
systemctl enable multipathd

check multipath

[root@node1 ~]# multipath -l
Oct 12 17:38:31 | vda: No fc_host device for 'host-1'
Oct 12 17:38:31 | vda: No fc_host device for 'host-1'
Oct 12 17:38:31 | vda: No fc_remote_port device for 'rport--1:-1-0'
mpatha (360014059c2719519e0f4445afbb30030) dm-2 LIO-ORG ,iscsi_store
size=10.0G features='0' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| `- 2:0:0:0 sda 8:0   active undef running
`-+- policy='service-time 0' prio=0 status=enabled
  `- 3:0:0:0 sdb 8:16  active undef running

manage configuration file

默认配置里，user_friendly_names yes 表示使用友好的名字，让我们自己能够方便去识别。

defaults {
        user_friendly_names yes
        find_multipaths yes
}

blacklist 里配置的是不配置多路径的磁盘。比如我们写devnode “^[vs]d[a-z]” ，那么vd开头的如vda到vdz开头的磁盘和sda到sdz开头的磁盘，都不会做多路径。

blacklist {
       wwid 26353900f02796769
        devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
        devnode "^[vs]d[a-z]"
}

blacklist_exceptions 里配置就是在blacklist里已经配置包含了的磁盘，但我们又要用的，就在这里写出来。

blacklist_exceptions {

        devnode "sd[a-z]"
}

配置multipath的别名

[root@node1 ~]# multipath -l
mpatha (360014059c2719519e0f4445afbb30030) dm-2 LIO-ORG ,iscsi_store
size=10.0G features='0' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| `- 2:0:0:0 sdb 8:16 active undef running
`-+- policy='service-time 0' prio=0 status=enabled
  `- 3:0:0:0 sda 8:0  active undef running
[root@node1 ~]# vim /etc/multipath.conf
multipaths {
        multipath {
                wwid                    360014059c2719519e0f4445afbb30030
                alias                   alvin_disk
        }
}
[root@node1 ~]# systemctl restart multipathd
[root@node1 ~]# multipath -l
alvin_disk (360014059c2719519e0f4445afbb30030) dm-2 LIO-ORG ,iscsi_store
size=10.0G features='0' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| `- 2:0:0:0 sdb 8:16 active undef running
`-+- policy='service-time 0' prio=0 status=enabled
  `- 3:0:0:0 sda 8:0  active undef running

查看默认配置,可以查看各种各样的一些厂商的一些设备。

multipathd -k
show
show config

为multipacth磁盘分区

fdisk /dev/mapper/alvin_disk
mkfs.ext4 /dev/mapper/alvin_disk1
mount /dev/mapper/alvin_disk1 /mnt/