My Personal Experience about Citrix XenServer 5.0
Posted by superman 
- on October 8th, 2008 in Virtualization, Xen | 13 Comments »
Yesterday Craig mentioned about 8 VCPU per VM on Citrix XenServer 5 is really a good stuff from Citrix and I must admit that.
I did a quick test and I would like to share my personal review about Citrix XenServer 5.0:
Personally I think network speed is fast compare to VMware ESX. I have a physical 1Gbps NIC network speed and I can get 2Gbps network speed after install XenTools on Windows 2008 server but require 2 times reboot(SuSE Linux require 1 reboot). Anyway VM guest shutdown and reboot process is faster than VMware ESX.
I was try to install SuSE Linux 10 using 4 ISO CD (both NFS or CIFS), the Citrix XenServer always give me an error “The VM rejected the attempt to detach the device xxxxx refusing to close” when switch ISO CD1 to ISO CD2. You have to extract 4 ISO CD into one single location to make it work or copy ISO to local storage(provider you have enough local disk space).
The enterprise product should not have similar issue and this is not make sense at all.
Anyway, you can try alternative way using “Install URL” instead of using ISO Image once you have extract ISO CD into single folder on your web server.
Install URL: http://xx.xx.xx.xx/inst/10/32/SP2/ALL
Advanced Boot OS Parameters:
console=ttyS0 xencons=ttyS hostip=xx.xx.xx.xx/24 gateway=xx.xx.xx.xx dnsserver=xx.xx.xx.xx
Please make sure your have correct IP, gateway and DNS setup properly else you will getting error during installation.
Add and remove any disk/storage on Window 2008 or SuSE Linux 10 no downtime or reboot required. The VM guest OS will detect automatically.
Convert to template and VM clone features which are another features behind VMware ESX.
Once you have converted to template, you won’t have another way to reverse back as VM guest machine. It’s one way operation which you will received a warning before convert to template as show below.
Right click VM guest, and click Copy VM will do VM cloning but require downtime. The Copy VM feature is disable during VM guest is power on.
Overall, I would said VMware ESX still my first choice.
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13 Responses
Looks like XEN from citrix are still far behind and need more efforts
Citrix XenServer does not support memory overcommit. You’re require sufficient physical RAM for your virtual guest.
Xen Server can’t exchange ISO image during the Virtual Machine setup as easy as VMware. That is really painful
Using Citrix Xen 5.0 Express (free as in beer) connected to a Netapp FAS or Dell Equalogic storage you can create a snapshot of a vm in a few seconds and then create a new vm from this snapshot as fast. Please don’t spread FUD! Memory over commit is not usefull in
IO and memory intensive production environments.
I just discovered that I can power up more than 4 VMs in Citrix XenServer Express 5.0.0 simultaneously. And, it can only allow maximum up to 3 virtual disk in one VM.
I will suspect is due to the express edition. Really need to get an evaluation copy for enterprise to test this out
I having difficulty create Redhat Linux. Do u have the same issue?
2008-06-09 3:18:49 PM Error: Creating ‘CentOS 5.1 x64′ by cloning ‘CentOS 5.1 x64′ – A timeout happened while attempting to attach a device OpaqueRef:27be456b-e28a-446f-eb5a-8171b01521a4 of type VBD to a VM
I looked at the machine and saw the following on the console:
xenbus dev backend/vdb/0/51712 error 2 creating vdb structure.
Leong, I guess you’re referring to clone Centos instead of Redhat Linux. My Xen sandbox destroy sometimes ago and I have never try Centos or Redhat on Xen. Sorry.
hmm… Yes, I saw most of the feedback related with windows only. Thanks superman.
Hi Nadav, Have you try ESX with “memory over commit” with DRS? Resources Priority is the key when you are consolidating or sharing. Features is not useful if you don’t know how to use. Maybe you could check with the guru — Craig.
Please note the network speed displayed in connection settings is a completely random number; I don’t understand how you fell for this…
The actual lan throughput to your lan or between vm’s on the same host might still be better than with VMWare due to paravirtualized drivers, but this is not related to those 2Gbps either. On the other hand VMWare offers a billion options for tweaking lan io that are yet unheard of in XenServer.
One more thing: If you run any guests without host tools installed, they can cripple the IO performance of all guests using the same physical host cpu. (think 400KB/s instead of 50MB/s lan performance, for example)
If you encounter strange performance drops that’s the first thing to check:
Logging in via SSH, use the “top” command and check for processes that sound like “qemu-dm”. If you see any, identify any VMs without Xenserver guest tools and fix them.
I hope this will prove a little more helpful than the other comments ;p
XenServer (with XenDesktop) has an edge for overall desktop virtualization strategy over VMware. If you have not committed to VMware in desktop virtualization space, take look at Citrix for its Xen Desktop (desktop provisioning/management/broker) + Provisioning Server (os streaming) + XenApp (application virtualization and streaming).
- happily running XenServer Enterprise 5.0 on a big honking box for desktop virtualization. not entirely biased towards Citrix as I have way more ESX than XenServer. Seems to me that Citrix has done a much better job in desktop space than VMware (undeniably, still leading the server virtualization space).
this post is more than 6 months now and we still yet to try the new release of Xen, hopefully they had overcome most of the issues in the previous version which reduce the pain of the customer should face. I think both vmware and Xen have their advantage and depend how you would want to use it and what you try to achieve.