Citrix Systems 6.1.0 manual Appendix B. Boot From SAN Environments

Appendix B. Boot From SAN Environments

Boot from SAN environments offer a number of advantages, including high performance, redundancy and space consolidation. In these environments, the boot disk resides on a remote SAN, and not on the local host. The diskless host communicates with the SAN through a host bus adapter (HBA), and the BIOS of the HBA contains the instructions that enable the host to find the boot disk.

Boot from SAN depends on SAN-based disk arrays with either hardware Fibre Channel or HBA iSCSI adapter support on the host. For a fully redundant boot from SAN environment, you need to configure multiple paths for I/O access. To do so, the root device should have multipath support enabled. For information on multipath availability for your SAN environment, consult your storage vendor or administrator. If you have multiple paths available, then you can enable multipathing in your XenServer deployment upon installation.

Warning:

Boot from SAN settings are not inherited during the upgrade process. When upgrading using the ISO or PXE process, customers should follow the same instructions as used in the installation process below to ensure that multipath is correctly configured.

To install XenServer to a remote disk on a SAN with multipathing enabled:

1.On the Welcome to XenServer screen, press F2.

2.At the boot prompt, enter multipath

XenServer boots to a remote disk on a SAN with multipathing enabled.

To enable filesystem multipathing using PXE installation, customers should add device_mapper_multipath=yes to the PXE Linux configuration file. An example configuration is as follows:

default xenserver label xenserver

kernel mboot.c32

append /tftpboot/xenserver/xen.gz dom0_mem=752M com1=115200,8n1 \ console=com1,vga --- /tftpboot/xenserver/vmlinuz \

xencons=hvc console=hvc0 console=tty0 \ device_mapper_multipath=yes \

--- /tftpboot/xenserver/install.img

For additional information on storage multipathing in your XenServer environment, please see the XenServer Administrator's Guide.

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