Red Hat Bugzilla – Bug 440115
Documentation needs to emphasize CLVM requirement for RHEL4 cluster
Last modified: 2009-08-19 23:29:00 EDT
Description of problem:
Customers are confused by LVM behavior when they try to use LVM on a RHEL4
cluster. Using LVM in a cluster requires CLVM (or HA-LVM).
This requirement needs to be noted throughout the documentation in all relevant
Version-Release number of selected component (if applicable):
Steps to Reproduce:
I sent the following proposal on 5-21-08 to Nick and Rob:
To address Bugs 440115, 440134, and 440133 (Documentation needs to emphasize
CLVM requirement for RHEL4 cluster), I plan to make the following updates to the
Red Hat cluster documentation for the RHEL 4.x and RHEL 5.x documentation. This
doesn't address the packaging question or the question of getting the warning to
customers in a more prominent place than within the documentation, but it's the
piece that we can provide within the documentation itself.
Please let me know if you have any questions or comments.
1. The LVM manual (all relevant releases)
a) I will add the following note to the section of the Introduction that
summarizes running LVM in a cluster (and mentions the clvmd daemon):
NOTE: Shared storage for use in Red Hat Cluster Suite requires that you be
running the cluster logical volume manager daemon (clvmd) or the High
Availability Logical Volume Management agents (HA-LVM). If you are not able to
use either the clvmd daemon or HA-LVM for operational reasons or because you do
not have the correct entitlements, you must not use single-instance LVM on the
shared disk as this may result in data corruption. If you have any concerns
please contact your Red Hat service representative.
b) The LVM Administrative Overview chapter includes a subsection on "Creating
LVM Volumes in a Cluster". I will add the same full note to that section.
c) In the section describing all the LVM commands, I will add this note right
after the first paragraph summarizing the chapter:
NOTE: If you are creating or modifying an LVM volume for a clustered
environment, you must ensure that you are running the clvmd daemon. For
information, see "Creating LVM Volumes in a Cluster".
2. Red Hat Cluster Suite Overview (both RHEL 4 and RHEL 5)
a) Section 1.6 of the Red Hat Cluster Suite Overview is a section on "Cluster
Logical Volume Manager". After the first introductory paragraph, I will add the
full note on shared storage.
b) Right at the beginning of the Cluster Suite Overview, in the Introduction,
there is a one-sentence summary of CLVM. I will add this note to that summary:
NOTE: When you create or modify a CLVM volume for a clustered environment, you
must ensure that you are running the clvmd daemon. For information, see "Cluster
Logical Volume Manager".
3.Configuring and Managing a Red Hat Cluster (both RHEL 4 and RHEL 5)
a) In the chapter on configuring Red Hat Cluster with Conga, there is a brief
subsection on "Configuring Cluster Storage". It refers to the LVM manual for
all CLVM information. I will add the full warning note about running the clvmd
b) In the chapter on configuring Red Hat Cluster with system-config-cluster,
there is a section on "Starting the Cluster Software". This already includes a
step on starting clvmd if there are clustered volumes. I think we can also add
the full note about running CLVMD or HA-LVM right here.
This would bring up the issue with running clvmd at every instance of CLVM
I made all the indicated changes for all versions of the documents and filed an
RT ticket to push the updated versions of the documents out to the documentation