centos 其他路径lib centos 多路径

1、Multipath介绍

一、Multipath简介

普通的电脑主机都是一个硬盘挂接到一个总线上，这里是一对一的关系。而到了有光纤组成的SAN环境，因为主机和存储经过了光纤交换机链接，这样的话，就构成了多对多的关系。也就是说，主机到存储能够有多条路径能够选择。主机到存储之间的IO由多条路径能够选择。node

二、实现功能

故障的切换和恢复linux

IO流量的负载均衡web

磁盘的虚拟化算法

2、实验环境

selinux iptables offshell

主机名

IP

操做系统

已有磁盘

安装服务

server1(客户端)

10.10.10.1(eth0)、172.25.254.1(eth1)

rhel7.3

sda、sdb

iscsi-initiator-utils(发现iscsi)、multipath

server2(服务器端)

10.10.10.2(eth0)、172.25.254.2(eth1)

rhel7.3

sda、sdb

targetcli.noarch(iscsi服务)

3、iscsi安装(服务器端)

一、安装iscsi

[root@server2 ~]# yum install -y targetcli.noarch

二、配置iscsi

[root@server2 ~]# targetcli
Warning: Could not load preferences file /root/.targetcli/prefs.bin.
targetcli shell version 2.1.fb41
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.
/> /backstores/block create dream:storage1 /dev/sdb
Created block storage object dream:storage1 using /dev/sdb.
/> /iscsi create iqn.2019-03.com.example:server2
Created target iqn.2019-03.com.example:server2.
Created TPG 1.
Global pref auto_add_default_portal=true
Created default portal listening on all IPs (0.0.0.0), port 3260.
/> /iscsi/iqn.2019-03.com.example:server2/tpg1/acls create iqn.2019-03.com.example:server2
Created Node ACL for iqn.2019-03.com.example:server2
/> /iscsi/iqn.2019-03.com.example:server2/tpg1/luns create /backstores/block/dream:storage1
Created LUN 0.
Created LUN 0->0 mapping in node ACL iqn.2019-03.com.example:server2
/> exit
Global pref auto_save_on_exit=true
Last 10 configs saved in /etc/target/backup.
Configuration saved to /etc/target/saveconfig.json

4、iscsi配置(客户端)

一、安装并加入认证

[root@server1 ~]# yum install -y iscsi-initiator-utils
[root@server1 ~]# vim /etc/iscsi/initiatorname.iscsi
InitiatorName=iqn.2019-03.com.example:server2

二、发现服务器端iscsi

[root@server1 ~]# iscsiadm -m discovery -t st -p 10.10.10.2
10.10.10.2:3260,1 iqn.2019-03.com.example:server2
[root@server1 ~]# iscsiadm -m discovery -t st -p 172.25.254.2
172.25.254.2:3260,1 iqn.2019-03.com.example:server2

三、登录

[root@server1 ~]# iscsiadm -m node -T iqn.2019-03.com.example:server2 -p 10.10.10.2 -l
Logging in to [iface: default, target: iqn.2019-03.com.example:server2, portal: 10.10.10.2,3260] (multiple)
Login to [iface: default, target: iqn.2019-03.com.example:server2, portal: 10.10.10.2,3260] successful.
[root@server1 ~]# iscsiadm -m node -T iqn.2019-03.com.example:server2 -p 172.25.254.2 -l
Logging in to [iface: default, target: iqn.2019-03.com.example:server2, portal: 172.25.254.2,3260] (multiple)
Login to [iface: default, target: iqn.2019-03.com.example:server2, portal: 172.25.254.2,3260] successful.

四、查看磁盘

能够发现多了sdc、和sdd二块磁盘，咱们不加入multipath会识别成二块磁盘，因此咱们能够加入mutipath防止网卡坏掉！！！json

[root@server1 ~]# fdisk -l
Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x00007256
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 616447 307200 83 Linux
/dev/sda2 616448 2715647 1049600 82 Linux swap / Solaris
/dev/sda3 2715648 41943039 19613696 83 Linux
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/sdc: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 4194304 bytes
Disk /dev/sdd: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 4194304 bytes

5、multipath安装及配置(客户端)

一、安装multipath

[root@server1 ~]# yum -y install device-mapper-multipath
[root@server1 ~]# modprobe dm-multipath
[root@server1 ~]# modprobe dm-round-robin
[root@server1 ~]# lsmod | grep dm_multipath
dm_multipath 23065 1 dm_round_robin
dm_mod 114430 3 dm_multipath,dm_log,dm_mirror
[root@server1 ~]# rpm -ql device-mapper-multipath ###查看生成文件
[root@server1 ~]# cp /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf /etc/
### 也能够经过下面命令生成配置文件
[root@server1 ~]# mpathconf --enable ###生成配置文件/etc/multipath.conf

二、查看wwid

[root@server1 ~]# /usr/lib/udev/scsi_id --whitelisted --device=/dev/sdc
360014056393309b846f47bcae82517a0

三、配置multipath

[root@server1 ~]# vim /etc/multipath.conf
defaults {
user_friendly_names yes
find_multipaths yes
}
multipaths {
multipath {
wwid 360014056393309b846f47bcae82517a0
alias mpathao
}
}
[root@server1 ~]# systemctl start multipathd
[root@server1 ~]# ls /dev/mapper/
control mpathao

四、格式化挂载

[root@server1 ~]# mkfs.xfs /dev/mapper/mpathao
meta-data=/dev/mapper/mpathao isize=512 agcount=4, agsize=1310720 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=5242880, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@server1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 19G 1.4G 18G 8% /
devtmpfs 227M 0 227M 0% /dev
tmpfs 237M 0 237M 0% /dev/shm
tmpfs 237M 4.7M 232M 2% /run
tmpfs 237M 0 237M 0% /sys/fs/cgroup
/dev/sda1 297M 119M 178M 41% /boot
tmpfs 48M 0 48M 0% /run/user/0
/dev/mapper/mpathao 20G 33M 20G 1% /data
[root@server1 ~]# mkdir /data
[root@server1 ~]# mount /dev/mapper/mpathao /data/
[root@server1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 19G 1.4G 18G 8% /
devtmpfs 227M 0 227M 0% /dev
tmpfs 237M 0 237M 0% /dev/shm
tmpfs 237M 4.7M 232M 2% /run
tmpfs 237M 0 237M 0% /sys/fs/cgroup
/dev/sda1 297M 119M 178M 41% /boot
tmpfs 48M 0 48M 0% /run/user/0
/dev/mapper/mpathao 20G 33M 20G 1% /data

五、查看状态

[root@server1 ~]# multipath -rr
[root@server1 ~]# multipath -ll

6、multipath配置简介

可用的节关键字以下:

- defaults:全局属性的默认设置。

- blacklist:黑名单，multipath会忽略黑名单中的设备。

- blacklist_exceptions:免除黑名单，加入黑名单内，但包含在这里的设备不会被忽略。

- multipaths:多路径相关配置。

- devices:存储设备相关配置。

配置文件：

uid_attribute:用udev的哪一个属性惟一标识一个设备，默认值为ID_SERIAL

path_grouping_policy ###路径分组策略

- failover ###一条路径一个组(默认值)

- multibus ###全部路径在一个组

- group_by_serial ###根据序列号分组

- group_by_prio ###根据优先级分组

- group_by_node_name ###根据名字分组

path_selector ###I/O操做算法

- service-time 0 ###选择IO服务时间最短的路径(默认值)

- round-robin 0 ###多个路径间不断循环

- queue-length 0 ###选择当前处理IO数最少的路径

failback ###回复失败管理

- immediate ###马上回复到活跃的优先级最高的组

- manual ###不操做，需自行处理

- followover ###第一个路径变为活动状态时应执行自动故障回复。 这能够防止节点在另外一个节点请求故障转移时自动失败。

no_path_retry ###多少次后禁止排队

- fail ###失败后就马上失败，没有排队

- queue ###一直进行排队，直到修复