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5.32. yaboot
The yaboot package is a boot loader for Open Firmware based PowerPC systems. It can be used to
boot IBM eServer System p machines.
• If the string that represents the path to kernel (or ramdisk) is greater than 63 characters, network
booting an IBM Power5 series system may result in the following error:
FINAL File Size = 8948021 bytes.
load-base=0x4000
real-base=0xc00000
DEFAULT CATCH!, exception-handler=fff00300
The firmware for IBM Power6 and IBM Power7 systems contains a fix for this issue.
5.33. xen
• As of Red Hat Enterprise Linux 5.4, PCI devices connected to a single PCI-PCI bridge can no longer
be assigned to different PV guests. If the old, unsafe behaviour is required, disable pci-dev-assign-
strict-check in /etc/xen/xend-config.sxp.
• In live migrations of paravirtualized guests, time-dependent guest processes may function
improperly if the corresponding hosts' (dom0) times are not synchronized. Use NTP to synchronize
system times for all corresponding hosts before migration.
• When running x86_64 Xen, it is recommended to set dom0-min-mem in /etc/xen/xend-config.sxp to
a value of 1024 or higher. Lower values may cause the dom0 to run out of memory, resulting in poor
performance or out-of-memory situations. (BZ#519492)
• The Red Hat Enterprise Linux 3 kernel does not include SWIOTLB support. SWIOTLB support
is required for Red Hat Enterprise Linux 3 guests to support more than 4GB of memory on AMD
Opteron and Athlon-64 processors. Consequently, Red Hat Enterprise Linux 3 guests are limited to
4GB of memory on AMD processors.
• When setting up interface bonding on dom0, the default network-bridge script may cause
bonded network interfaces to alternately switch between unavailable and available. This
occurrence is commonly known as flapping.
To prevent this, replace the standard network-script line in /etc/xen/xend-config.sxp
with the following line:
(network-script network-bridge-bonding netdev=bond0)
Doing so will disable the netloop device, which prevents Address Resolution Protocol (ARP)
monitoring from failing during the address transfer process.
• The Hypervisor outputs messages regarding attempts by any guest to write to an MSR. Such
messages contain the statement Domain attempted WRMSR. These messages can be safely
ignored; furthermore, they are rate limited and should pose no performance risk.
The following note applies to x86_64 Architectures:
136
(BZ#508310)
(BZ#426861)
138
(BZ#504187)
(BZ#429154
yaboot
(BZ#550086)
137
140
141
BZ#429154)
,
142
(BZ#477647)
135
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