On Thu, Jul 05, 2007 at 10:35:21AM -0400, Chris Hoogendyk wrote:
> The one thing that is annoying is that on /var/mail an incremental is
> essentially the same as a full. Those mail files (one per account) are
> just like a database file -- add or remove one message and you have to
> back up the whole file. It would be interesting to write a wrapper to do
> incremental mail dumps sort of like the sql database programs that do
> incremental dumps. I wonder if there would be any demand for such a
> thing. It could get a little messy, and would probably require the
> Application API. In our case, we have about 1200 accounts/files. It
> would require reading headers and doing proper locking so as not to
> collide with the mail programs.
Yes, I think there would be demand for that (there are a lot of
application-specific things that could use better backups). And yes, it
will be a lot easier after the Application API is in place :)
> I'm guessing that for those changers where it's all tied up in one scsi
> address, and/or where there are multiple drives in a library, it might
> be desirable to have changer handle it. Then my case becomes the special
> case -- the changer is set up in sgen.conf and has a scsi device
> address, and the tape drive is set up in st.conf and is /dev/rmt/1 -- so
> the changer does not know how the drive got set up. This special case
> might require the changer to look somewhere else, e.g. amanda.conf, to
> find out. But, then, couldn't it also tell somehow if there had been an
> override? Or does that get too messy?
That's basically the answer -- the current changer interface has no
provision for passing along overrides, and adding one would potentially
break a lot of custom changer scripts. You've hit the nail on the head
as to why changers provide devices to Amanda, rather than leaving her to
use tapedev.
> Ok, maybe we just need to document that when someone overrides tapedev
> they should also override tpchanger if they have one.
See the attached patch.
Dustin
--
Dustin J. Mitchell
Storage Software Engineer, Zmanda, Inc.
http://www.zmanda.com/
Index: man/xml-source/amanda.8.xml
===================================================================
--- man/xml-source/amanda.8.xml (revision 423)
+++ man/xml-source/amanda.8.xml (working copy)
@@ -1221,15 +1221,36 @@
</refsect1>
<refsect1><title>CONFIGURATION OVERRIDE</title>
-<para>Most command allow to overwrite any configuration parameter on
-the command line with the -o option.</para>
-<para>-o NAME=value</para>
-<para>eg. -o runtapes=2</para>
-<para>eg. -o DUMPTYPE:no-compress:compress="server fast"</para>
-<para>eg. -o TAPETYPE:HP-DAT:length=2000m</para>
-<para>eg. -o INTERFACE:local:use="2000 kbps"</para>
+<para>Most commands allow the override of specific
+configuration options on the command line, using the <arg
+choice="plain">-o</arg> option. This option has the form <arg
+choice="plain">-o</arg><replaceable>name</replaceable>=<replaceable>value</replaceable>.
+An optional space is allowed after the <arg choice="plain">-o</arg>.
+Each configuration option should be specified in a separate
+command-line option.</para>
+<para>For global options, <replaceable>name</replaceable> is simply the name
of the option, e.g.,
+<programlisting>
+amdump -oruntapes=2
+</programlisting>
+For options in a named section of the configuration,
<replaceable>name</replaceable> has the
+form
<replaceable>SECTION</replaceable>:<replaceable>section_name</replaceable>:<replaceable>name</replaceable>,
where <replaceable>SECTION</replaceable> is one of TAPETYPE, DUMPTYPE,
HOLDINGDISK, or INTERFACE, and <replaceable>section_name</replaceable> is the
name of the tapetype, dumptype, holdingdisk, or interface. Examples:
+<programlisting>
+amdump -o TAPETYPE:HP-DAT:length=2000m
+amdump -o DUMPTYPE:no-compress:compress="server fast"
+amdump -o HOLDINGDISK:hd1:use="-100 mb"
+amdump -o INTERFACE:local:use="2000 kbps"
+</programlisting>
+</para>
+<para>Note that configuration overrides are not effective for tape
+changers, which supply a tapedev based on their own configuration. In order to
+override <emphasis remap="I">tapedev</emphasis>, you must also disable any
changer:
+<programlisting>
+amdump -otapedev=/dev/nst1 -otpchanger=''
+</programlisting>
+</para>
+
</refsect1>
<refsect1><title>AUTHOR</title>
