Red Hat ENTERPRISE 5.4 RELEASE NOTES, Manual

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cmirror
291
The following note applies to the ia64 Architecture:
• If your system only has 512MB of RAM, attempting to install Red Hat Enterprise Linux 5.4 may fail.
To prevent this, perform a base installation first and install all other packages after the installation
finishes.
(BZ#435271)
15
4.2. cmirror
The cmirror packages provide user-level utilities for managing cluster mirroring.
• Due to limitations in the cluster infrastructure, cluster mirrors greater than 1.5TB cannot be created
with the default region size. If larger mirrors are required, the region size should be increased from
its default (512kB), for example:
# -R <region_size_in_MiB>
lvcreate -m1 -L 2T -R 2 -n mirror vol_group
Failure to increase the region size will result in the LVM creation process hanging and may cause
other LVM commands to hang.
(BZ#514814)
16
4.3. compiz
Compiz is an OpenGL-based window and compositing manager.
• Running
rpmbuild
on the
compiz
source RPM will fail if any KDE or
qt
development packages
(for example,
qt-devel
) are installed. This is caused by a bug in the
compiz
configuration script.
To work around this, remove any KDE or
qt
development packages before attempting to build the
compiz
package from its source RPM.
(BZ#444609)
17
4.4. device-mapper-multipath
The device-mapper-multipath packages provide tools to manage multipath devices using the device-
mapper multipath kernel module.
• When using
dm-multipath
, if
features "1 queue_if_no_path"
is specified in
/etc/
multipath.conf
then any process that issues I/O will hang until one or more paths are restored.
To avoid this, set
no_path_retry [N]
in
/etc/multipath.conf
(where
[N]
is the
number of times the system should retry a path). When you do, remove the
features "1
queue_if_no_path"
option from
/etc/multipath.conf
as well.
If you need to use
"1 queue_if_no_path"
and experience the issue noted here, use
dmsetup
to edit the policy at runtime for a particular LUN (i.e. for which all the paths are unavailable).
To illustrate: run
dmsetup message [device] 0 "fail_if_no_path"
, where
[device]
is
the multipath device name (e.g.
mpath2
; do not specify the path) for which you want to change the
policy from
"queue_if_no_path"
to
"fail_if_no_path"
.
(BZ#419581)
18
• When a LUN is deleted on a configured storage system, the change is not reflected on the host. In
such cases,
lvm
commands will hang indefinitely when
dm-multipath
is used, as the LUN has
now become
stale
.