HP StoreFabric Converged Network Adapters - Manual (Page 13)

Troubleshooting 13
Troubleshooting
Linux installation and configuration known issues
The following issues are known for Linux installation and configuration.
Memory considerations for Linux OS
The Broadcom bnx2x driver uses virtual memory for DMA operations. Normally, the driver requires a virtual
memory size of 8264 kB per physical function at the probe stage. At the open stage, the driver requires more
than 256 kB of virtual memory per physical function. On architectures that the default vmalloc size is
relatively small and not sufficient to load many interfaces, use vmalloc=<size> during the boot to increase
the size.
A 32-bit Linux operating system has a limited amount of memory space available for kernel data structures.
To decrease the amount of memory pre-allocated by the driver to use the Broadcom bnx2x driver on the
platform, do one of the following:
• Limit the number of RX queues with the num_queues driver parameter.
• Limit the number of RX buffers for each queue with the ethtool -G option.
During the installation of a 32-bit Linux operating system, HP recommends setting bnx2x.num_queues=1
in the kernel command line when the system boots up from the installation media to install the OS. The
bnx2x.num_queues=1 setting avoids potential out-of-memory issues.
Multipath configuration for Linux OS
HP recommends the guidelines in Native Linux Device-Mapper Multipath for HP Storage Disk Arrays
Reference Guide to configure multipath on Linux systems. For more information, search Native Linux
Device-Mapper Multipath for HP Storage Disk Arrays Reference Guide on the HP SPOCK website
(
http://www.hp.com/storage/spock ). For Broadcom CNAs, HP also recommends a fast_io_fail_tmo
value of 25 in multipath.conf for each storage array. Add the line fast_io_fail_tmo 25 to any
array that does not already have the value defined. The adjustment avoids a race condition that can result in
unexpected target and LUN loss.
Boot from SAN on RHEL 6 for Linux OS
Certain RHEL 6 configurations might experience boot-time IO errors when configured to boot from SAN. To
avoid a potential problem, when the RHEL 6 installer prompts for the initial reboot after installation, press
Ctrl-Alt-F2 to enter a shell. Edit /mnt/sysimage/boot/grub/menu.lst, and then enter
bnx2x.disable_tpa=1 in the default kernel command line.
VMware installation and configuration known issues
The following issues are known for VMware installation and configuration.