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Today speak of a task very easy, in some cases, can be a headache for administrators who come from Windows.

At times, the support team may request certain system logs for review.

XenCenter has an option to generate a zip file that contain information on logs and system commands.
But, as we import logs if we do not have XenCenter? see how to import specific logs with old method.

For do this, you need a ssh/scp software o use any terminal for connect to xenserver. I talk how do it from MAC/Linux and from Windows.


Only need to run a terminal/Shell and use the command scp for do this. How? See this.

Note. You need to know the exact path that containt the file that you need import.

If you need recover the messages log, for example, in your desktop terminal type:






# scp root@ c:UserscristiansanDesktop

Windows SO

How i do on Windows if we haven’t terminal?

All administrators know putty for SSH connections.
Another imprescidible tool for admins is winscp. Winscp, is a client sftp.

Log on XenServer with winscp gui and use a similar to FTP GUI interface for upload and download files from/to XenServer.

I don’t explain this tool because is very easy. Try it!


Putty: http://www.putty.org/
WinSCP: http://winscp.net/
Man SSH  Man SCP

Another resource in this blog related with this: SSH key: MAC/LINUX to XenServer without PASS

A few days ago, we had an incident with one client that he lost the connection with iscsi LUN where have the VM HDD.

The StorageRepository appear with de red blade and isn’t possible «reattach» process. When you do the action, we have the next message:

The attempt to query the iSCSi daemon failed

We don’t found error reported on Support Forums. In the logs of system i can see:

XenServer Log

ERROR XenAdmin.Actions.AsyncAction [3600] – The attempt to query the iSCSi daemon failed

ERROR XenAdmin.Actions.AsyncAction [3600] – en XenAdmin.Actions.SrRepairAction.Run() en XenAdmin.Actions.AsyncAction.RunWorkerThread(Object o)


Raising exception [86, Failed to query the iscsi daemon [opterr=Failed to logout from target]]

FAILED: (errno 5) stdout: », stderr: ‘ Volume group «VG_XenStorage-cc734a73-5a5f-5fd1-24cf- 308258bc1fd2» not found’

We tested in XenServer that you can validate with openiscsi perfectly but isn’t posible connect to LUN. Is strange because all other LUN in the NAS is not affected.

We destroy de PBD connector and recreate again, with de the same problem.

The customer talk with NAS Manufacturer and is necessary update de Firmware. It’s posible a NAS error, but if this the problem, how i recover the VMs on this LUN.

In this post i don’t  explain how to troublesshot de iscsi connection. I explain how to recover the LUN across the Live Linux Distribution.  Any LiveCD is valid.

You only need to run Linux SO. The first step is install the necessary packets for do the recuperation. You only need the OpeniScsi packets. LVM2 is optional if you like to try mount the filesystem.

We talk with the client and ask that is necessary to create a LUN with the same size that the corrupted lun. With this, i create a VM with XenServer and run the liveCD.

When the Linux Live is running, we need to open a terminal and install the necessary packets.

# sudo apt-get install open-iscsi

When the install is finished is time to connect with Lun and recover the information.  For do this…

Start iscsi daemon

# /etc/init.d/open-iscsi start

Discover targets

#iscsiadm -m discovery -t sendtargets -p [IP_Target]

IP_TARGET:3260,1 iqn.2002-10.com.target:RESOURCE1

IP_TARGET:3260,1 iqn.2002-10.com.target:RESOURCE2

IP_TARGET:3260,1 iqn.2002-10.com.target:RESOURCE3

establish the credentials

# iscsiadmin -m node -t IP_TARGET:3260,1 iqn.2002-10.com.target:RESOURCE1 -P [IP_Target] -o update -n node.session.auth.username -v [USER]

# iscsiadmin -m node -t IP_TARGET:3260,1 iqn.2002-10.com.target:RESOURCE1 -P [IP_Target] -o update -n node.session.auth.password-v [PASSWD]

and now connect to target

# iscsiadm -m node -t IP_TARGET:3260,1 iqn.2002-10.com.target:RESOURCE1 -p [IP_Target] -l

with fdisk -l, you can see the device used. In my case we use /dev/sdb.

Realice the same process for the New LUN created. Is mapped with the next device available. In my case: /dev/sdc

In this point is the moment for recover the info. And how i do?

It’s easy, we do a copy block to block from sdb device to sdc device.  For do this, we type the next command:

# dd if=/dev/sdb of=/dev/sdc bs=512 conv=noerror,sync

The process is slow and take his time. You can see if the command is running with TOP command or PS command. When the command is finished is time to create again the SR on XenCenter. The new SR with the old SR copy is ready to use.

For more info about this, i recommended read the man pages:




¿Do you need help with your Citrix Enviroments?

Visit us at www.ctxdom.com or contract us at www.101-consulting.com

In certain monitored environment with EdgeSight, you can detect problems DataCollectors platform by which the consumption of CPU (CPU only, as the single thread process) performed by fbserver.exe is 100%.

% Processor Time: Before Exclusion Fbserver Detail


This results in a total consumption of a CPU and generating Dumps Rscorsrv.exe process.

The solution is to exclude the process ctxxmls.exe in the ZDC server.

We perform the following:

  • Open connection to server DataCollector
  • Open the registry (cmd -> regedit)
  • Locate the following registry path:
    • HKLMSYSTEMCurrentControlSetServicesRskcore
  • Edit the key: UviProcessList (or UviProcessExcludes)
  • Add this key to the process: ctxxmls.exe

%Processor Time: Fbserver Detail After Exlude Proceess


¿Do you need help with your Citrix Enviroments?

Visit us at www.ctxdom.com or contract us at www.101-consulting.com

Prepare XenServer for DVS

abril 4th, 2012 | Posted by cristiansan in Appliance | DVs | XenServer - (0 Comments)

2 years ago (October 2012) I wrote in ctxdom.com about #Citrix Virtual Distributed Switch.

You can read this article on the Following linkctxdom.com

There is a very important little point in implementing DVS. -Enable it on XenServer.

To perform this task, we logon on XenServer and run the following command inCLI.

xe-switch-network-backend openvswitch

This is very important, and that redirects all internal traffic through DVS and allows the performance of various tasks such as:
ACLs and QoS Policies; NetFlow; Traffic mirroring, Port Bonding & Per VMtraffic policy.

More info: http://support.citrix.com/article/CTX129669

If you need Disable this funtionality, you need run this command:
(dvs use can cause certain problems of congestion in some environment)

xe-switch-backend network-bridge

It is important to know the procedure to run this configuration. These are the recommendations:

1.Disable HA (before Any maintenance).
2.Migrate VMs off of host.
3.Enable bridge mode via command line: xe-switch-backend-network [bridgeoption]
5.Migrate VMs back.
6.Enable HA.

¿Do you need help with your Citrix Enviroments?

Visit us at www.ctxdom.com or contract us at www.101-consulting.com

Hi to all, and welcome again to my stupid blog 😛

Today i write about how connect with your XenServer without pass key on the ssh connection. This tutorial is base on a Mac SO but is equal to do on a Linux/Unix SO.

First you need generate the PassKey on your Mac. For this try with:


Follow the intructions. When you finish, it generate a file on /home/user/.ssh/ named id_rsa and a public key named id_rsa.pub.

The first is your identification and the second the public key.

Now, you only need copy the file id_rsa.pub and add the content file on the authorized_keys file on the XenServer.

For copy the key, i use the command SCP. For do it, put:

scp /home/USER/.shh/id_rsa.pub root@

and now, putt he content of id_rsa.pub to the file Authorized_keys with the command:

cat ./id_rsa.pub >> /root/.shh/authorized_keys

Now is time the connect without password on XenServer. See  the step by step process on the next video.


XenServer: Create a VM from CLI

septiembre 29th, 2011 | Posted by cristiansan in CLI | XenServer - (0 Comments)

A Virtual Machine (VM) is a software computer that, like a physical computer, runs an operating system and applications. The VM is comprised of a set of specification and configuration files and is backed by the physical resources of a host. Every VM has virtual devices that provide the same functionality as physical hardware, and can have additional benefits in terms of portability, manageability, and security.


I talk about XenServer CLI and how do things with the Shell. Now i talk about how create VMs on XS5.6.

Install a VM with XenCenter is easy. But, maybe is necessary create a VM across the Shell. How i do it?

Run the Shell on XenServer or connect across Putty or another SSH client and run the next commands.

Install VM from Template:

 xe vm-install new-name-label=<VM_NAME> template=<TEMPLATE NAME>

*This command return the UUID of the Machine

List the ISOs available:

 xe cd-list

Putt he ISO into the virtual CD drive

 xe vm-cd-ad vm=<VM_NAME> cd-name=<NAME_ISO.iso> device=3

Start and instal the OS:

 xe vm-start vm=<VM-NAME>

In this point is necessary the XenCenter Console, because the VM console isn’t see with the CLI on XenServer. See how to install a VM with CLI.

Yo can see a list of VM templates with the next command:

 xe template-list

we create the VM with a Template:

and XS return the UUID of the VM.

and i can see on XenCenter the new VM:

Now it’s moment to see the ISO available with the comand xe cd-list.

I use this ISO for install 2008R2. For this…

 you can use <tab> for autocomplete the ISO name or VM name 😉

 And now, it’s moment to Start de VM: