Iscsi disk multi-path

Function Description

The Application Server accesses the same storage space of multiple iSCSI servers through multiple different network paths, so that the iSCSI disk of the application server has a certain high availability.

Environment Description

1. hao storage system: the three-node Hao storage system is used as an example: (server1 server2 server3) 2. application Server: operating system version CentOS-5.6-x86_643. application Server dependency package: Device-mapper-multipath (under centos)

Multi-path Configuration
Modify/etc/multipath. conf. For details, see the following example:

Blacklist {devnode "^ SDZ"} defaults {limit 10 packet failover packet fail limit Yes} multipaths {multipath {wwid limit alias mdssda packet failover path_selector "round-robin 0" failback 0 rr_weight priorities no_path_retry 0} multipath {wwid 24d445305520342340330000011000450007cdbe24e043000 00 alias mdssdb path_grouping_policy multibus path_selector "round-robin 0" failback 0 rr_weight priorities no_path_retry 0} Add a Multipath configuration domain to each disk. Obtain the wwid using the following method: [[email protected] ~] # Scsi_id -- whitelisted -- device =/dev/SDA (SDA is the disk created for iSCSI, centos6) 14d4453000000000002000000000000007cdbe24e00000000 [[email protected] ~] #/Sbin/scsi_id-g-u-s/block/SDA (SDA is the disk created for iSCSI, centos5) 14d4453000000000002000000000000007cdbe24e00000000 after configuration is complete, start the multipath service: [[email protected] ~] #/Etc/init. d/multipathd start [OK] [[email protected] ~] # Multipath-F clear a mounted multi-path device [[email protected] ~] # Multipath-l view mounted multi-path Devices

Usage

1. create an iSCSI Device (target/Lun) in the Hao storage system. 2. the application server connects three iSCSI servers to the same disk. the multipath device is/dev/mapper/mdssda (Multipath. name configured in conf)

H2
H3.windows client multi-path

In Windows, the iSCSI client is "Microsoft iSCSI software initiator", which is:

http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=18986

To use an iSCSI disk in multi-path mode, select
Microsoft mpio multipathing support for iSCSI
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After the installation is complete, open the software and switch to the "discovery" tab.
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Click "add", add the IP addresses of the servers where multiple yiscsi instances are located, and click "OK"
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Switch to the "targets" tab. All logon targets on yiscsi are displayed.
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Select the target you want to log on to and click "Log on ..." Button to bring up the logon dialog box
If you use the multi-path method, select "enable multi-path" and click "Advanced ..." Button,
Target Portal: select a server, enter the user name and password, and click "OK" to log on.
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Repeat the above process. Target Portal: select the remaining servers one by one, enter the user password, and click "OK" to log on.
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After successful logon, the target status changes to "connected".
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In Windows disk management, you can see the connected Disk
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Log out, select the target you want to exit, click "details", select the Pre-session check box in the pop-up dialog box, and click "log off ..."

Iscsi disk multi-path