From bbf74a76024ce5eb344de076c2250282c4b0864e Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Sun, 14 Mar 2010 16:39:00 +0100
Subject: [PATCH] Update instance modify documentation
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
---
doc/admin.rst | 27 +++++++++++++++++++++++++++
man/gnt-instance.sgml | 14 ++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/doc/admin.rst b/doc/admin.rst
index 89941c0b4..51a879462 100644
--- a/doc/admin.rst
+++ b/doc/admin.rst
@@ -512,6 +512,33 @@ command::
Note that this will fail if the disks already exists.
+Conversion of an instance's disk type
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+It is possible to convert between a non-redundant instance of type
+``plain`` (LVM storage) and redundant ``drbd`` via the ``gnt-instance
+modify`` command::
+
+ # start with a non-redundant instance
+ gnt-instance add -t plain ... INSTANCE
+
+ # later convert it to redundant
+ gnt-instance stop INSTANCE
+ gnt-instance modify -t drbd INSTANCE
+ gnt-instance start INSTANCE
+
+ # and convert it back
+ gnt-instance stop INSTANCE
+ gnt-instance modify -t plain INSTANCE
+ gnt-instance start INSTANCE
+
+The conversion must be done while the instance is stopped, and
+converting from plain to drbd template presents a small risk, especially
+if the instance has multiple disks and/or if one node fails during the
+conversion procedure). As such, it's recommended (as always) to make
+sure that downtime for manual recovery is acceptable and that the
+instance has up-to-date backups.
+
Debugging instances
+++++++++++++++++++
diff --git a/man/gnt-instance.sgml b/man/gnt-instance.sgml
index 1436bcc96..b8ed14b3a 100644
--- a/man/gnt-instance.sgml
+++ b/man/gnt-instance.sgml
@@ -1397,6 +1397,13 @@ instance5: 11225
<arg>--disk <replaceable>N</replaceable>:mode=<replaceable>MODE</replaceable></arg>
</group>
+ <sbr>
+ <arg>-t<group choice="req">
+ <arg>plain</arg>
+ <arg>drbd</arg>
+ </group></arg>
+
+
<sbr>
<arg>--submit</arg>
<sbr>
@@ -1416,6 +1423,13 @@ instance5: 11225
in the form of <userinput>name=value[,...]</userinput>. For details which options can be specified, see the <command>add</command> command.
</para>
+ <para>
+ The <option>-t</option> option will change the disk template
+ of the instance. Currently only conversions between the
+ plain and drbd disk templates are supported, and the
+ instance must be stopped before attempting the conversion.
+ </para>
+
<para>
The <option>--disk
add:size=<replaceable>SIZE</replaceable></option> option
--
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