Installation guide

All Architectures

• If your system uses the TSC timer, the gettimeofday system call may move backwards. This is

because of an overflow issue that causes the TSC timer to jump forward significantly in some cases;

when this occurs, the TSC timer will correct itself, but will ultimately register a movement backwards

in time.

This issue is particularly critical for time-sensitive systems, such as those used for transaction

systems and databases. As such, if your system needs precision timing, Red Hat strongly

recommends that you set the kernel to use another timer (for example, HPET).

• Attempting to run sniff may result in an error. This is because some required packages are not

installed with dogtail.

To prevent this from occurring, install the following packages manually:

• librsvg2

• ghostscript-fonts

• pygtk2-libglade

• Thin Provisioning (also known as "virtual provisioning") will be first released with EMC Symmetrix

DMX3 and DMX4. Please refer to the EMC Support Matrix and Symmetrix Enginuity code release

notes for further details.

• In /etc/multipath.conf, setting max_fds to unlimited will prevent the multipathd

daemon from starting up properly. As such, you should use a sufficiently high value instead for this

setting.

• SystemTap currently uses GCC to probe user-space events. GCC is, however, unable to provide

debuggers with precise location list information for parameters. In some cases, GCC also fails to

provide visibility on some parameters. As a consequence, SystemTap scripts that probe user-space

may return inaccurate readings.

• The IBM T41 laptop model does not enter Suspend Mode properly; as such, Suspend Mode will

still consume battery life as normal. This is because Red Hat Enterprise Linux 5 does not yet include

the radeonfb module.

To work around this, add a script named hal-system-power-suspend to /usr/share/hal/

scripts/ containing the following lines:

chvt 1

radeontool light off

radeontool dac off

This script will ensure that the IBM T41 laptop enters Suspend Mode properly. To ensure that the

system resumes normal operations properly, add the script restore-after-standby to the

same directory as well, containing the following lines:

radeontool dac on

radeontool light on

chvt 7