http://www.xendesktopmaster.com/how-to-add-an-additional-local-disk-to-your-xenserver-5-5-host/
http://www.ruslansivak.com/2010/3/29/XenServer-55–Converting-Local-Storage-to-ext3-and-thereby-enabling-sparse-provisioning
http://www.schirmacher.de/display/INFO/How+to+add+additional+disks+to+XenServer+host
http://kiekeboe100.hoefman.be/blog/2009/06/attaching-disk-to-xenserver-guest/
http://everyrandom.com/blog/?p=89
I am considering moving the Xenserver machines to a network location, removing them from the box in which the hypervisor is residing.
I have a gigabit network which theoretically can transport just over 100MB/s worth of data (about 125MB/s I think is the calculation) but I expect less then that in the real world.
A 100Mb network can do 12.5MB/s, but realistically, only about 9MB/s is capable after all the networking overhead is introduced, so assuming 90MB/s for a gigabit connection may not be unreasonable.
HD normally put out 40-60MB/s, so a gigabit network should not be a bottleneck (assuming only one connection).
Going to run some tests to see what throughput my LAN can sustain.
Running bonnie++ on /mnt/tower/disk1 I get
Version 1.03d ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP apps-server05 2072M 22582 11 23699 1 15228 0 53534 35 62733 1 165.6 0 ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 832 2 1852 1 1079 1 812 1 2153 0 840 1
Locally on the workstation running Bonnie++ on the SSD drive with a 8gig file (4gigs ram in machine) I get:
Version 1.03d ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP workstation01 7416M 63910 62 49520 20 24627 11 96748 92 233131 38 2300 9 ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
On the same workstation, using a 7200rpm 160 gig drive, I get:
To be done
I did some file copies with SCP (since it reports the transfer rate).
Between machines on the xen hypervisor with a local file I am getting about 75MB/s
Between same machines, with a file stored on the UnRAID server I am getting about 30MB/s in read speed. This is obviously limited by both the UnRAID machine or the network connection.
Did another SCP between my workstation machine and a virtual machine and I topped out at 9.9MB/s
Will have to investigate this further since I’m obviously only getting 100Mbit speeds, when I have a 1Gb connection? Maybe not…
I had tried using Suse Studio appliances a while back, and didn’t have much luck with it. That was over a year ago, and honestly, I don’t remember exactly why I didn’t like it, or couldn’t get it working. I think it may have had something to do with the fact that I could not boot one of those appliances in xen or xenserver (whatever I was running at the time)
Anyway, it seems like there may be home. I came back to visit the site today, and did a bit of digging, and it seems there may be a simple way to convert the xen appliance into a Cirtix XenServer appliance. Get the python script and read the how-to here.
I will have to give this a go.
UPDATE: So I gave it a go.
After some struggling, I can report success. I have managed to get a xen vm created by suse studio to run in Citrix’s XenServer, using the script mentioned earlier.
Once the xva file is imported into xenserver (throught xen center) I need to add “console=ttyS0 xencons=ttyS barrier=off” to the Properties > Startup options of the VM.
Currently I’m refining the one SqueezeCenter appliance VM.
A few days ago I moved from runing a openSuSE DomU host to the Free XenServer 5.5.0 that Citrix is offering.
I had noticed that the VMs were running very slowly. Much slower then I remembered them running on the openSuSE DomU. So I did some tests, and it came down to the fact that hdparm -tT /dev/sda was reporting about 1-2MB/sec for the buffered disk reads. This was taken at the console of the xenserver terminal, not on a VM.
After some research, I found out that the generic IDE drivers don’t allow for UDMA to be enabled. So I did the next best thing. I had a SATA drive of similar size in another machine, and swapped the two.
Now I get about 60MB/sec buffered disk reads. That’s what it should be. And from within a VM I get about 55MB/sec, but I don’t quite believe that. Will have to do some more extensive testing with bonnie++.
I’ve been running virtual machines for a while now (maybe 3 years?) and they have all been running on some bare minimal OpenSuse installation (in Dom U) with Xen being the hypervisor.
I decided the other day to give XenServer 5.5.0 (the free version) a try. I had a few days of unhappiness, mainly because I love openSuse, and it seemed that nobody knew how to get it installed in XenServer, as a PV guest.
I finally got it working. Finally got openSuSE 11.2 running in XenServer, as a PH guest, with the Server Tools installed and working. Continue reading
A couple of links which I know will come in handy later:
So after installing OpenSuSE 11.2 on the server machine, I decided to take a step back nd decide how to manage all the current and future virtual machine.
For starters, I will use LVM for the disk space they use. I have created a template/minimal install of OpenSuse11.2 into a file based VM. The file disk it’s installed on is 1GB. gzipped, the file is only 250MB.
This will be the basis/starting point for all the new VMs. I have used dd to copy the virtual file based disk to an LVM volume on any size. Once that’s done, I can resize the partition to whatever size I want. (Note 1 on resizing) I can also make as many copies I want and run them as anything I want.
As I was trying to figure out how to copy a LVM volume, I came across this. Interesting way of using LVM snapshots to manage multiple copies of the same OS. Continue reading
I am curious to find in my environment how much worse a file based VM is at file access vs one that is based on a physical partition.
File based VMs are much easier to manage and backup, but at what cost? Continue reading
I am not liking SuSe Studio so much anymore. The main goal for using it was to easily and quickly build xen VMs that I could deploy on my xen server at home. Continue reading