Differences between version 13 and predecessor to the previous major change of XenNotes.
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| Newer page: | version 13 | Last edited on Monday, May 21, 2007 12:33:15 pm | by CraigBox | Revert |
| Older page: | version 4 | Last edited on Tuesday, July 4, 2006 12:19:43 am | by AristotlePagaltzis | Revert |
@@ -1 +1,49 @@
-Describe
[XenNotes
] here
.
+!!!ntpdate(1) has no effect
+Xen by default just uses the dom0's clock, which isn't updated within the domU's. Either set <tt>/proc/xen/independent_wallclock</tt> to 1 (so that this domU has an indepedent clock from the host dom0, or set the clock in the dom0.
+
+!!!Making a tape drive available to a guest via iSCSI
+__This is specifically for ~XenSource's range of products, although the principles will of course work in other Xen implementations__
+
+I recently had a scenario where I was replacing two Windows servers with ~XenServer guests. This was fine, but we needed a way to backup to the existing SCSI DDS4 DAT drive. After failing to make PCI passthrough work, I settled on the much nicer method of providing the tape drive via an iSCSI target on the ~XenServer Host (Dom0). Here is how I achieved this.
+
+Note 1: This is totally unsupported by ~XenSource
+
+Note 2: I've used the ~XenSource terminology "host" instead of Dom0, as this applies to the ~XenSource commercial implementation of Xen. It will probably work fine on OSS Xen, but you can just install the normal kernel dev packages and ignore the DDK stuff.
+
+* Download the
[Xen DDK|http://tx.downloads.xensource.com/products/ddk/index.php
]
+* The DDK is an ISO containing a VM with a development environment. Import it to your Xen host, and start it.
+* Download [iscsitarget .4.14|http://optusnet.dl.sourceforge.net/sourceforge/iscsitarget/iscsitarget-.4.14.tar.gz] (you MUST use this version, as the patch for rawio support will not cleanly apply to .4.15) into your DDK VM.
+* Download the patch for [rawio support|http://sourceforge.net/mailarchive/attachment.php?list_name=iscsitarget-devel&message_id=1170171101.2822.23.camel@localhost.localdomain&counter=1] into your DDK VM (assuming you're saving it in /tmp)
+* Now do the following:
+<pre>
+yum install kernel-devel bison flex
+tar -zxvf iscsitarget-.4.14.tar.gz
+cd iscsitarget-.4.14
+patch -p0 < /tmp/raw.p
+make
+</pre>
+* scp the entire iscsitarget-.4.14 directory to your destination Xen host, and on that host do:
+<pre>
+yum install make gcc
+cd iscsitarget-.4.14
+make install
+mkdir /lib/modules/2.6.16.38-xs3.2..531.3960xen/kernel/iscsi
+cp kernel/iscsi_trgt.ko /lib/modules/2.6.16.38-xs3.2..531.3960xen/kernel/iscsi
+depmod -aq
+</pre>
+
+The last three steps are required because <tt>make install</tt> will not copy the kernel module correctly outside the target environment.
+
+* Now edit your <tt>/etc/ietd.conf</tt> and configure the tape as per the following example snippet:
+<pre>
+Target iqn.2007-04.com.example:tape0
+ Lun 0 H=1,C=,I=6,L=,Type=rawio
+ Type 1
+</pre>
+
+* Save and do <tt>/etc/init.d/iscsi-target start</tt>
+* Modify <tt>/etc/sysconfig/iptables</tt> to allow port 3060 tcp from the IP addresses running the initiator.
+* Attach to the target using the initiator of your choice
.
+
+-----
+CategoryXen
