Multi-path ing of Huawei S5500T on Redhat6.4

Environment Description: Storage: Huawei S5500T server: Huawei RH5885V2 Operating System: linuxRedHat6.464bit Problem description: after the operating system is installed on the server, the local disk starts with sda by default. When the corresponding lun is divided and mapped to the corresponding server, the order of the local disk and the mapped lun has changed. For example, three Luns are allocated to the corresponding server in the disk array.

Environment Introduction:

Storage: Huawei S5500T server: Huawei RH5885 V2 Operating System: linux RedHat6.4 64bit

Problem description:

After the operating system is installed on the server, the local disk starts with sda by default. When the corresponding lun is divided and mapped to the corresponding server, the order of the local disk and the mapped lun has changed. For example, after dividing three Luns on a disk array to the corresponding server and ing them to the server, the drive letter starts with sd * and is dominated by the drive letter of the disk array (as explained by Huawei storage engineers ), the local disk is directly placed in the back.

Disk before ing
[Root @ localhost ~] # Fdisk-l

Disk/dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065*512 = 8225280 bytes
Sector size (logical/physical): 512 bytes/512 bytes
I/O size (minimum/optimal): 512 bytes/512 bytes
Disk identifier: 0x0000add9

Device Boot Start End Blocks Id System
/Dev/sda1*1 66 524288 83 Linux
Partition 1 does not end on cylinder boundary.
/Dev/sda2 66 458 3145728 82 Linux swap/Solaris
Partition 2 does not end on cylinder boundary.
/Dev/sda3 458 2611 17300480 83 Linux

Mapped Disk
[Root @ localhost ~] # Fdisk-l

Disk/dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065*512 = 8225280 bytes
Sector size (logical/physical): 512 bytes/512 bytes
I/O size (minimum/optimal): 512 bytes/512 bytes
Disk identifier: 0x0000add9

Device Boot Start End Blocks Id System
/Dev/sda1*1 66 524288 83 Linux

Disk/dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065*512 = 8225280 bytes
Sector size (logical/physical): 512 bytes/512 bytes
I/O size (minimum/optimal): 512 bytes/512 bytes
Disk identifier: 0x0000add9

Device Boot Start End Blocks Id System
/Dev/sdb1*1 66 524288 83 Linux

Disk/dev/sdc: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065*512 = 8225280 bytes
Sector size (logical/physical): 512 bytes/512 bytes
I/O size (minimum/optimal): 512 bytes/512 bytes
Disk identifier: 0x0000add9

Device Boot Start End Blocks Id System
/Dev/sdc1*1 66 524288 83 Linux

Disk/dev/sdz: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065*512 = 8225280 bytes
Sector size (logical/physical): 512 bytes/512 bytes
I/O size (minimum/optimal): 512 bytes/512 bytes
Disk identifier: 0x0000add9

Device Boot Start End Blocks Id System
/Dev/sdz1*1 66 524288 83 Linux
Partition 1 does not end on cylinder boundary.
/Dev/sdz2 66 458 3145728 82 Linux swap/Solaris
Partition 2 does not end on cylinder boundary.
/Dev/sdz3 458 2611 17300480 83 Linux

What problems will this cause? Next, you need to mount the ing disk to deploy the application later, which is similar to the following operations:

Mount/dev/sda1/data/
Mount/dev/sdb1/data/B
Mount/dev/sdc1/data/c

So far, the program has been running normally. Suddenly the power was shut down at the server, but the call was made later. This is the case now. The RH5885 V2 server of Huawei is automatically started. When the disk array is not started, the relevant personnel will start the disk array, after a period of time, applications on the server will not be used.

The cause of the problem is as follows:

First: Normally, you should first start the disk array and then start the server. When the server is started, you can shut down the server normally, then start the disk array, and then start the server, so that the application can be used normally.
Note: The reason is that the server is shut down normally. At that time, the operator directly presses the shutdown button in front of the server, and then starts the disk array and then starts the server. The result server cannot access the system because grub. the conf file is lost. (This is not a frequent occurrence. As a result, we are lucky enough to meet this problem. We will fix grub later. conf, normally enters the system)

Second, when using a disk array, you can disable the auto-start feature of the server. Huawei's RH5885 V2 server can only disable this feature on the Management port. Start the disk array and then start the server, so that the application can be used normally.

Third: Can I set the ing drive letter for multi-path ing? For example, the ing drive letter should not start with sd * (the reply given by Huawei engineers at the time cannot be changed, the disk array ing of hongshu does not start with sd, so I personally think it can be changed.) later, I will communicate with Huawei engineers to obtain the UUID mapped to the disc, the binding method in/etc/fstab is as follows:

1. Obtain the uuid of the ing disc and the format of the file system

Here, the ing disc is sda1, sdb1, sdc1, and the local disk is sdz.

Blkid/dev/sda1
8e8265ce-f9cc-46e0-a952-14fa7a000062c
Blkid/dev/sdb1
8e8265ce-f9cc-46e0-a952-14fa7a31663c
Blkid/dev/sdc1
8e8265ce-f9cc-46e0-a952-14fa7a3166dc

2. Add a ing disk to the/etc/fstab file.

In this way, the server is started first, and the sequence of attaching and ing disks after the disk array is started will not be messy, because sda has been empty.

UUID = 8e8265ce-f9cc-46e0-a952-14fa7a000062c/dev/sdb1 ext4 defaults 0 0
UUID = 8e8265ce-f9cc-46e0-a952-14fa7a31663c/dev/sdc1 ext4 defaults 0 0
UUID = 8e8265ce-f9cc-46e0-a952-14fa7a3166dc/dev/sdd1 ext4 defaults 0 0

3. Deploy the application later to mount the ing disk to the directory

Mount/dev/sdb1/data/
Mount/dev/sdc1/data/B
Mount/dev/sdd1/data/c

4. You can also directly add the ing disk to the directory in the fstab file (not tested)

UUID = 8e8265ce-f9cc-46e0-a952-14fa7a000062c/data/a ext4 defaults 0 0
UUID = 8e8265ce-f9cc-46e0-a952-14fa7a000063c/data/B ext4 defaults 0 0
UUID = 8e8265ce-f9cc-46e0-a952-14fa7a3166dc/data/c ext4 defaults 0 0

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