Administer > SA Provisioning > OS sequence-based provisioning > Multipath SAN support for OS provisioning

Multipath SAN support for OS provisioning

SA provides multipath SAN support for the topics listed in this section.

OS sequences

Red Hat 6 automatically identifies multipathing and enables kernel modules, but Red Hat 5 does not.

For Red Hat 5, before you run a Red Hat Enterprise Linux (RHEL) 5 OS Sequence, use the following steps to pass MPATH as a kernel argument for the server:

  1. Define a custom attribute kernel_arguments for the server, and set its value to mpath. See Custom Attributes for Linux or VMware ESX.
  2. Create the OS Installation Profile.
  3. Add a custom attribute to the Installation profile, and set its value to mpath.
  4. Set the value of the installation profile to mpath.

If you are performing multipath installation, it is also recommended that you add mpath as the kernel argument in the Red Hat 5 kickstart file. You can do this by creating a copy of the Configure Default Red Hat 5 ks.cfg and modifying the file.

SUSE Linux Enterprise Server 11

SUSE Linux Enterprise Server 11 does not identify multipathing by default. Use the procedures in this section to install SUSE Linux Enterprise Server on multipath LUNs.

Updating multipath drivers

You must copy the drivers into the media to enable multipathing. More information about the driver update disk (DUD) and the process of updating the media is available here:

http://www.novell.com/support/viewContent.do?externalId=7009981&sliceId=1

To configure SA, you must perform the following tasks:

  1. Download the driver update disk (DUD) from the above link.
  2. Extract the contents of the DUD to the SUSE Linux Enterprise Server 11 media.
  3. Upload the SUSE Linux Enterprise Server 11 media to the SA Media Server using the import_media command.
  4. If you already have the media uploaded into the SA Media Server, extract the contents of the DUD as directed by the SUSE support document.

After you complete these steps, multipathing will be enabled for all subsequent installations. To perform non-multipathed installations, create a separate SUSE media within SA Media Server.

Defining kernel arguments

To enable multipath installation, pass mpath as a value for the custom attribute kernel_argument by doing one of the following:

  • When creating the OS Installation Profile, define the custom attribute kernel_argument and set its value to mpath.
  • Before running the SUSE Linux Enterprise Server 11 OS sequence, define a custom attribute kernel_argument on the server to be provisioned, and set its value to mpath.

Partitioning section in AutoYaST

SUSE Linux Enterprise Server 11 requires that devices be specified in Mapper format during multipath environment installations. SA OS Provisioning verifies the AutoYaST profile and modifies it to suit the multipathing environments, based on the following rules:

 

Case

SA Solution

  1. AutoYaST does not have the partitioning section.

SA adds the partitioning section with the drive and device.
  1. AutoYaST has a single drive section, but does not have a device section.

SA inserts the boot drive expressed in Mapper format.
  1. AutoYaST has multiple drive sections, but does not have device sections. Has multiple drive sections but no <device> in <drive> section.

SA does not make any changes to AutoYaST. It prints a warning and continues with the installations.

This type of configuration can cause installation failure. To ensure a successful installation, complete each of the drive sections with devices in Mapper formats.
  1. AutoYaST has devices in the configuration Single _OR_ multiple drive sections and a <device> specified for the <drive>.

SA checks if the drive attributes in AutoYaST are in the correct Mapper format. If they are not, SA prints a warning and makes no further checks for correctness.

If the drive attributes are not in the correct format, the installation fails. To ensure a successful installation, complete each of the drive sections with devices in Mapper formats.

Friendly device name

/dev/mapper devices should only be used during installation. The SUSE Linux Enterprise Server Storage Administration Guide states that, in the running system, the multipath devices should be accessed through /dev/disk/by-id/.

SA sets up the scripts to convert the devices from /dev/mapper to /dev/disk/by-id when you define the custom attribute friendly_mpath_device to true.

Windows 2008/ Windows 2008 R2

Windows supports installations in multipath environments. Install multipath Device Specific Modules (DSMs) to further improve the capabilities of the target server. Import these DSMs into the SA Software Repository and install them using software policies attached to OS sequences.

You can modify the SAN Policy for the Windows Service OS (Winpe32, winpe64, winpe32-ogfs, winpe64-ogfs) shipped with SA. For more information about available options, see:

http://technet.microsoft.com/en-us/library/cc749466(v=ws.10).aspx

The default SAN Policy registry value in the SA-provided Windows pre-installation environment (WinPE) boot image is 1.

VMWare ESX/ESXi

VMWare ESX and ESXi support multipathing - no additional steps are required.

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