Why do multiple mock disks appear on the application server after the log on operation is repeatedly performed?

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Every time when the log on operation is performed on an AS, a session is established between the AS and the storage system. Based on the session, the operating system (OS) of the AS scans the mapped LUNs. If the multipathing software is not installed, the OS cannot determine whether the LUNs scanned from several physical paths are the same LUN, and assumes them as different LUNs (the number of LUNs is equal to the times of performing the log on operation); therefore, multiple mock disks appear on the AS. If the multipathing software is installed, it can determine whether the LUNs in different sessions are the same LUN by analyzing the world wide name (WWN) of each LUN, and eliminates the mock disks.

Other related questions:
Reason why redundant disks appear in an AIX application server on an IP SAN network
The AIX application server is connected to the Ethernet switch through a network cable. The switch is connected to two iSCSI host ports on the same controller of the storage device through two network cables. When a LUN is mapped to the AIX application server, the AIX application server detects redundant disks. To enhance the data transfer reliability, an application server and a storage array are usually connected over multiple paths. If the multipathing software is unavailable, those multiple paths translate into multiple redundant disks, which confuse the actual number of disks. In the Ethernet networking, the AIX application server does not support the multipathing software. Therefore, redundant disks are detected on the AIX application server. On a Fibre Channel network, AIX application servers support the multipathing software.

Why the number of hard disks scanned by the application server is a multiple of the number of hard disks mapped to the application server?
The multipathing software is not installed. If the multipathing software is not installed, the OS cannot determine whether the LUNs scanned from several physical paths are the same LUN, and assumes them as different LUNs; therefore, multiple mock disks appear on the AS. If the multipathing software is installed, it can determine whether the LUNs in different sessions are the same LUN by analyzing the world wide name (WWN) of each LUN, and eliminates the mock disks. In this way, the number of hard disks scanned by the AS is the number of LUNs actually mapped to the AS. You can obtain the installer of the multipathing software from the delivery-attached CD-ROM and install the program according to the actual OS.

Server boot disk
ServiceCD2.0 is an intelligent boot disk for servers. It provides OS installation and RAID configuration functions. ServiceCD2.0 has the following features: - Provides wizard-based installation of OSs, such as Windows Server, SUSE, Red Hat, and VMware ESXi and installs device drivers based on the hardware detected. - Provides a graphical user interface to help you complete the installation. - Supports configuration of a variety of RAID controller cards through a unified GUI. You can use the boot disk (ServiceCD) delivered with the server to perform the installation. You can also download the iso file of the boot disk (ServiceCD) and perform the installation over remote control. For details about How do I download the iso and install the OS, see: http://support.huawei.com/ecommunity/bbs/10179917.html

Why does an application server fail to detect the mapped virtual disks after being configured with the UltraPath for Windows software?
The possible causes for a virtual disk detection failure include: ? The UltraPath for Windows software is incompatible with the Windows operating system installed on the application server. ? The UltraPath for Windows software is incompatible with the storage array. ? The LUNs are mapped to the application server before being formatted. ? The bit version of the UltraPath for Windows installation package is incompatible with that of the operating system running on the application server. For example, the application server runs a 32-bit operating system but uses a 64-bit installation package. ? The application server does not detect any physical disks, so it cannot produce virtual disks. ? The driver of physical disks is not replaced. The respective troubleshooting measures to the previous six causes are: 1. Confirm that the UltraPath software is installed on its supported operating system. The UltraPath for Windows-supported operating systems are Windows Server 2008 Enterprise Edition x86 SP1 and later, Windows Server 2008 Enterprise Edition AMD64, Windows Server 2003 Enterprise Edition x86 SP1 and later, Windows Server 2003 Enterprise Edition AMD64 SP1 and later, and Windows Server 2000 SP4. 2. UltraPath for Windows only supports the storage arrays from Technologies Co., Ltd. 3. Wait until the LUNs are formatted, and then scan for them on the application server. 4. Ensure that the operating system version is compatible with the installation package. If an inappropriate installation package has been installed, uninstall it first, restart the operating system, and then install the package of the proper version. 5. Check whether the physical links are normal. If they are normal, ensure that the LUNs are normal in the storage array and successfully mapped to the application server. 6. Check that the driver of physical disks is replaced. ? If the UltraPath software is not installed, before the installation, go to the C:\windows\inf directory and open all the inf files starting with oem. In each file, search for the following keywords: MPIODisk, Detected\MPIO, and Root\HWDSM. If a file contains one of the keywords, delete this oem.inf file and its related oem.pnf file. After ensuring that none of the oem.inf files contains the keywords, you can install the UltraPath software. ? If the UltraPath software is already installed, choose Computer Management > Device Manager > Disk Drivers to view the driver information of physical disks. If the driver of a physical disk is not mpdev.sys, the driver has not been replaced. Uninstall the faulty physical disk and rescan for disks. ? During service idle hours, restart the application server.

Reason why the application server breaks down if the storage system is powered off unexpectedly when I/O operations on file systems and raw disks are performed on the Solaris application server
Reason why the application server breaks down if the storage system is powered off unexpectedly when I/O operations on file systems and raw disks are performed on the Solaris application server: FAQ-Why Does the Application Server Break Down If the Storage System Is Powered Off Unexpectedly When I/O Operations on File Systems and Raw Disks Are Performed on the Solaris Application Server

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