When multipath start when it gets UUID (universally unique identify) proc / partitions inside all block devices through the system command scsi_id -eg -s / block / sdX, then all have the same UUID block device composed of a Group, in / dev / mapper production corresponding to a separate device. When the device is ready to use to generate parted or fdisk partition, the partition can use kpartx command to register, and then you can use the system command to create a file system and mount.
Usually in the series installation process will install device-mapper package using the command rpm linux comes with inquiries about whether a package has been installed times. Use the command rpm -ivh installation, install the following rpm package:
Starting Multipath and Multipath Configuration
Starting Multipath, the default template is created by mpathconf command. Create a default configuration, launch and activation multipathd process, you can use the following command:
mpathconf --enable --with_multipathd y
After configuration is recommended to restart the multipathing software:
Note: in / etc / next generation after the completion of startup files and generate bindings and multipath.conf wwid in / etc / multipath, which wwid recorded in the system tray all mounted disc unique ID, Bindings record corresponding to the ID Mapping after the disc is generally binding will produce similar mpathx and other documents in the / dev / mapper
Notes ------------------------------------------------- -----
If there is no generation can follow Deploying Oracle RAC 11g R2 Database on Red Hat EnterpriseLinux 6
To operate in the following manner:
1. As the root user, install the device-mapper-multipath package using the yum package
# Yum install device-mapper-multipath
2. Copy the multipath.conf file found within /usr/share/doc/device-mapper-multipath-0.4.9/
to / etc /
# Cp /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf / etc /
3. Capture the scsi id of the local disk (s) on the system.
# Scsi_id --whitelisted --replace-whitespace --device = / dev / sda
4. Uncomment and modify the blacklist section within the /etc/multipath.conf file to include
the scsi id of the local disk on the system. Once complete, save the changes made to
the multipath.conf file.
devnode "^ (ram | raw | loop | fd | md | dm- | sr | scd | st) [0-9] *"
devnode "^ hd [a-z]"
5. Start the multipath daemon.
# Service multipathd start
Starting multipathd daemon: [OK]
6. Enable the multipath daemon to ensure it is started upon boot time.
# Chkconfig multipathd on
7. Identify the dm- device, size, and WWID of each device mapper volume for Oracle
OCR and voting disks, data disks and recovery disks. In this example, volume mpathb
It is identified via the following command:
# Multipath -ll
Figure Multipath Device (mpathb)
8. Uncomment the defaults section found within the /etc/multipath.conf file.
udev_dir / dev
path_selector "round-robin 0"
getuid_callout "/ lib / udev / scsi_id --whitelisted
--device = / dev /% n "
NOTE: The standard options can be customized to better fit your storage array's
capabilities. Check with your storage vendor for details.
9. Un-comment the multipath section found within the /etc/multipath.conf file and create
an alias for each device mapper volume in order to enable persistent naming of those
volumes. Once complete, save the changes made to the multipath.conf file. The output
should resemble the example below. For reference, refer the Oracle data volumes
created for the reference environment as displayed in Table 2.4.3: Oracle OCR,
Voting Disk, & Data File Sizes.
10.Restart the device mapper multipath daemon.
# Service multipathd restart
Stopping multipathd daemon: [OK]
Starting multipathd daemon: [OK]
11.Verify the device mapper paths and aliases are displayed properly. Below is an
example of one device mapper device labeled fra.
# Multipath -ll
fra (3600c0ff000d7e7a89e85ac5101000000) dm-10 HP, MSA2324fc
size = 186G features = '1 queue_if_no_path' hwhandler = '0' wp = rw
| - + - Policy = 'round-robin 0' prio = 130 status = active
| | - 3: 0: 0: 3 sdd 8:48 active ready running
| | - 3: 0: 1: 3 sdh 8: 112 active ready running
| | - 4: 0: 0: 3 sdt 65:48 active ready running
| `- 4: 0: 1: 3 sdx 65: 112 active ready running
`- + - Policy = 'round-robin 0' prio = 10 status = enabled
| - 3: 0: 2: 3 sdl 8: 176 active ready running
| - 3: 0: 3: 3 sdp 8: 240 active ready running
| - 4: 0: 2: 3 sdab 65: 176 active ready running
`- 4: 0: 3: 3 sdaf 65: 240 active ready running
By default, DM-Multipath use most multi-path provides configuration value. In addition, DM-Multipath supports most common support DM-Multipath storage array. The default configuration values and the supported devices, please refer /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf.defaults file.
You can edit /etc/multipath.conf override the default configuration of the DM-Multipath. If necessary, you can also configure the file does not support the storage array may default.
Multipath configuration file can be divided into the following sections:
It is not considered a specific list of equipment and more paths.
Lists are not blacklisted multipath device according to blacklist section parameters.
DM-Multipath general default settings.
Characteristics of each individual multipath device settings. These values cover specified in the defaults and devices section of the configuration file values.
Each set of the storage controller. These values cover the defaults section of the configuration file of the specified value. If you're not a default supported storage arrays, you may need to create devices sub-section for your array.
When the system determines the attributes of a multipath device, first it checks the multipath settings, then the settings on each device, and then the multipath system defaults.
After the above configuration, start multipathd process, the device will automatically scan the process started at / dev / mapper directory can see generating equipment, such as: mapth4
1. Use the multipath command to check whether the path is normal,
[Root @ dbserv1 mapper] # multipath -d -l
2. Use fdisk command system partition, use the command kpartx l / dev / mapper / mpath4 view the partition information
3. If you can not find use kpartx d / dev / mapper / mpath4 partition command register
4. If the case of using ASM disk management, the next step is to configure partitions by udev permissions and aliases, so that Oracle ASM in the configuration process can be seen in these partitions. The configuration procedure in the next article about udev will be described.
5. Of course, you can also use Oracle ASMLib to configure the ASM disks, this relatively udev way when a little trouble, but also a corresponding benefit in that the excess out of the space in the ASM configuration by allowing the OS file system identified.
6. If you do not Rac, in a single-node environment, use mke2fs -j / dev / mapper / mapth4p1 create a file system on the corresponding partition
7. Use the mount command to mount the file system can be used.
Multipath basic maintenance commands
1. Commitment multipath:
/etc/init.d/multipathd stop / start / reatart
2. Check the current link status and disk multipathing situation:
3. Remove the multipath device:
4. Re-scanning device:
5. When a new device is added in the DM-Multipath, the new devices will be located in the / dev directory in two different positions:
/ Dev / mapper / mpathn
/ Dev / dm-n
/ Dev / mapper devices are generated during the boot process. You can use these devices to access the multipath device, for example when creating logical volumes
All / dev / dm-n devices format for internal use only, please do not use them