Virtualization Blog

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XenServer Dundee Beta 1 Available

We are very pleased to make the first beta of XenServer Dundee available to the community. As with all pre-release downloads, this can be found on the XenServer Preview page. This release does include some potential commercial features, and if you are an existing Citrix customer you can access those features using the XenServer Tech Preview. It's also important to note that a XenServer host installed from the installer obtained from either source will have identical version number and identical functionality. Application of a Tech Preview license unlocks the potential commercial functionality. So with the "where do I get Dundee beta 1" out of the way, I bet you're all interested in what the cool bits are, and what things might be worth paying attention to. With that in mind, here are some of the important platform differences between XenServer 6.5 SP1 and Dundee beta 1.

Updated dom0

The control domain, dom0, has undergone some significant changes. Last year we moved to a 64 bit control domain with a 3.10 kernel as part of our effort to increase overall performance and scalability. That change allowed us to increase VM density to 1000 VMs per host while making some significant gains in both storage and network performance. The dom0 improvements continue, and could have a direct impact on how you manage a XenServer.

CentOS 7

dom0 now uses CentOS 7 as it's core operating system, and along with that change is a significant change in how "agents" and some scripts run. CentOS 7 has adopted systemd, and by extension so too has XenServer. This means that shell scripts started at system initialization time will need to change to follow the unit and service definition model specified for systemd.

cgroups for Control Isolation

Certain xapi processes have been isolated into Linux control groups. This allows for greater system stability under extreme resource pressure which has created a considerably more deterministic model for VM operations. The most notable area where this can be observed is under bootstorm conditions. In XenServer 6.5 and prior, starting large numbers of VMs could result in start operations being blocked due to resource contention which could result in some VMs taking significantly longer to start than others. With xapi isolation into cgroups, VM start operations no longer block as before resulting in VM start times being much more equitable. This same optimization can be seen in other VM operations such as when large quantities of VMs are shutdown.

RBAC Provider Changes

XenServer 6.5 and prior used an older version of Likewise to provide Active Directory. Likewise is now known as Power Broker, and XenServer is using the Power Broker Identity Services to provide authentication for RBAC. This has improved performance, scale and reliability, especially for complex or nested directory structures. Since RBAC is core to delegated management of a XenServer environment, we are particularly interested in feedback on any issues users might have with RBAC in Dundee beta 1.

dom0 Disk Space Usage

In XenServer 6.5 and prior, dom0 disk space was limited to 4GB. While this size was sufficient for many configurations, it was limiting for more than a few of you. As a result we've split dom0 disk into three core partitions; system, log and swap. The system partition is now 18GB which should provide sufficient for some time to come. This also means that the overall install space required for XenServer increases from 8GB to 46GB. As you can imagine, given the importance of this major change, we are very interested to learn of any situations where this change prevents XenServer from installing or upgrading properly.

Storage Improvements

Having flexible storage options is very important to efficient operation of any virtualization solution. To that end, we've added in support for three highly requested storage improvements; thin provisioned block storage, NFSv4 and FCoE.

Thin Provisioned Block Storage

iSCSI and HBA block storage can now be configured to be thinly provisioned. This is of particular value to those users who provision guest storage with a high water mark expecting that some allocated storage won't be used. With XenServer 6.5 and prior, the storage provider would allocate the entire disk space which could result in a significant reduction in storage utilization which in turn would increase the cost of virtualization. Now block storage repositories can be configured with an initial size and an increment value. Since storage is critical in any virtualization solution, we are very interested in feedback on this functional change.

FCoE

Fibre Channel over Ethernet is protocol which allows Fibre Channel traffic to travel over standard ethernet networks. XenServer now is able to communicate with FCoE enabled storage solutions, and can be configured at install time to allow boot from SAN with FCoE. If you are using FCoE in your environment, we are very interested in learning both any issues as well as learning what CNA you used during your tests.

Operational Improvements

Many additional system level improvements have been made for Dundee beta 1, but the following highlight some of the operational improvements which have been made.

UEFI Boot

XenServer 6.5 and prior required legacy BIOS mode to be enabled on UEFI based servers. With Dundee beta 1, servers with native UEFI mode enabled should now be able to install and run XenServer. If you encounter a server which fails to install or boot XenServer in UEFI mode, please provide server details when reporting the incident.

Automatic Health Check

XenServer can now optionally generate a server status report on a schedule and automatically upload it to Citrix Insight Services (formerly known as TaaS). CIS is a free service which will then perform the analysis and report on any health issues associated with the XenServer installation. This automatic health check is in addition to the manual server status report facility which has been in XenServer for some time.

Improved Patch Management in XenCenter

Application of XenServer patches through XenCenter has become easier. The XenCenter updates wizard has been rewritten to find all patches available on Citrix’s support website, rather than ones that have been installed on other servers. This avoids missing updates, and allows automatic clean-up of patches files at the end of the installation.

Why Participate in the Beta Program

These platform highlights speak to how significant the engineering effort has been to get us to beta 1. They also overshadow some other arguably core items like a move to the Xen Project Hypervisor 4.6, host support for up to 5TB of host RAM or even Windows guest support for up to 1TB RAM. What they do show is our commitment to the install base and their continued adoption of XenServer at scale. Last year we ran an incredibly successful prerelease program for XenServer Creedence, and its partly through that program that XenServer 6.5 is as solid as it is. We're building on that solid base in the hopes that Dundee will better those accomplishments, and we're once again requesting your help. Download Dundee. Test it in your environment. Push it, and let us know how it goes. Just please be aware that this is prerelease code which shouldn't be placed in production and that we're not guaranteeing you'll ever be able to upgrade from it.

Download location: http://xenserver.org/prerelease

Defect database: https://bugs.xenserver.org

Review: XenServer 6.5 SP1 Training CXS-300
XenServer Dundee Alpha.3 Available

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Comments 36

Ezequiel Mc Govern on Tuesday, 22 September 2015 19:15

Ceph SR suppport is On the roadmap?

0
Ceph SR suppport is On the roadmap?
Guest - Nick on Thursday, 05 November 2015 00:34

+1 for Ceph!!

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+1 for Ceph!!
Guest - Dan David on Saturday, 26 September 2015 14:55

Just curious, does Dundee finally introduce support for something else than the archaic ext3 file system for local repositories (not everyone is operating a SAN)? And has the process of creating a local ISO repository been addressed, or it it the same hassle as with 6.x?

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Just curious, does Dundee finally introduce support for something else than the archaic ext3 file system for local repositories (not everyone is operating a SAN)? And has the process of creating a local ISO repository been addressed, or it it the same hassle as with 6.x?
Tim Mackey on Monday, 28 September 2015 15:31

Dan,

I'll need to check the local SR file system, but think its still ext3. Local storage is an important use case, so I'm curious what benefits you'd see to moving to something other than ext3 for local storage in a XenServer environment?

Nothing has changed wrt using a portion of local storage for ISOs. Unfortunately we don't often hear about this use case, so if you could provide some details on your environment, that would be good. Things like number of local SRs, disk config, if the ISO SR is physically shared with VDIs - stuff like that.

-tim

-tim

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Dan, I'll need to check the local SR file system, but think its still ext3. Local storage is an important use case, so I'm curious what benefits you'd see to moving to something other than ext3 for local storage in a XenServer environment? Nothing has changed wrt using a portion of local storage for ISOs. Unfortunately we don't often hear about this use case, so if you could provide some details on your environment, that would be good. Things like number of local SRs, disk config, if the ISO SR is physically shared with VDIs - stuff like that. -tim -tim
Guest - Dan David on Friday, 02 October 2015 16:54

It's not just SSDs as mentioned, there are other issues like the 32TB limit (these days exceeded even by many homeservers), godawful performance at parallel i/o, no extends, no live check or defrag. Frankly, it should have already been replaced many years ago.

Since the dom0 is CentOS this really begs the question why XFS isn't used. Not only is XFS the default file system for CentOS 7 (and REL 7), it's a proven modern enterprise file system that allows online checking and defrag, plus it excels in situations with a lot of parallel i/o like on a typical virtualization host. And it supports up to 500TB which is more in line with the storage realities of 2014.

It seems a bit silly to go to great length to stick to the old cludge ext3 when the base OS for XenServer uses something much more appropriate as default file system. Hell, even the free Microsofts Hyper-V Server comes with something better than ext3 (NTFS), and does so for many years.

As to the ISO repository, as I said before not everyone uses a SAN, and smaller setups tend to store ISO files locally. On Hyper-V or a Linux box I can just put the files in a folder (which can even be remote accessible) and am done. On XS I still have to jump to unsupported manual hurdles just to get something so basic.

You say that you consider local storage as an important use case but quite frankly its hard to keep a straight face when the relevant parts are so awfully neglected, especially when the neglect seems to continue in the next XS release.

0
It's not just SSDs as mentioned, there are other issues like the 32TB limit (these days exceeded even by many homeservers), godawful performance at parallel i/o, no extends, no live check or defrag. Frankly, it should have already been replaced many years ago. Since the dom0 is CentOS this really begs the question why XFS isn't used. Not only is XFS the default file system for CentOS 7 (and REL 7), it's a proven modern enterprise file system that allows online checking and defrag, plus it excels in situations with a lot of parallel i/o like on a typical virtualization host. And it supports up to 500TB which is more in line with the storage realities of 2014. It seems a bit silly to go to great length to stick to the old cludge ext3 when the base OS for XenServer uses something much more appropriate as default file system. Hell, even the free Microsofts Hyper-V Server comes with something better than ext3 (NTFS), and does so for many years. As to the ISO repository, as I said before not everyone uses a SAN, and smaller setups tend to store ISO files locally. On Hyper-V or a Linux box I can just put the files in a folder (which can even be remote accessible) and am done. On XS I still have to jump to unsupported manual hurdles just to get something so basic. You say that you consider local storage as an important use case but quite frankly its hard to keep a straight face when the relevant parts are so awfully neglected, especially when the neglect seems to continue in the next XS release.
Guest - fbifido on Wednesday, 28 October 2015 17:28

+1 for XFS

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+1 for XFS
Senol Colak on Thursday, 01 October 2015 13:19

Hi Tim,

simple, ext3 is not supporting SSD drives with TRIM. You need ext4 to get TRIM support. After the successfull installations I always delete the default VG partition to reformat it on ext4 with trim support. From my point of view it is mendatory to have ext4 support.

Thx.

Senol

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Hi Tim, simple, ext3 is not supporting SSD drives with TRIM. You need ext4 to get TRIM support. After the successfull installations I always delete the default VG partition to reformat it on ext4 with trim support. From my point of view it is mendatory to have ext4 support. Thx. Senol
Tobias Kreidl on Thursday, 01 October 2015 16:18

As long as you're not messing with IntelliCache (which may depend on ext3), it's pretty easy to just update even your existing ext3 filesystems to ext4. Also, for large local file systems, ext4 can mean a huge improvement in fsck times, literally from hours down to a few minutes. Having official ext4 support would certainly be desirable and in all likelihood, should be an easy update.

0
As long as you're not messing with IntelliCache (which may depend on ext3), it's pretty easy to just update even your existing ext3 filesystems to ext4. Also, for large local file systems, ext4 can mean a huge improvement in fsck times, literally from hours down to a few minutes. Having official ext4 support would certainly be desirable and in all likelihood, should be an easy update.
Guest - fbifido on Thursday, 29 October 2015 13:12

+1 for TRIM

0
+1 for TRIM
Guest - Diogo on Friday, 02 October 2015 14:11

What should the best way to update to the new partitions layout, is their a way?

Or must do a clean install?

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What should the best way to update to the new partitions layout, is their a way? Or must do a clean install?
Tobias Kreidl on Sunday, 04 October 2015 02:51

Generally for alpha and beta releases of XenServer, there is no upgrade functionality built in or intended, but when a final release comes about, clearly there needs to be a way to do so. Hence for now, a clean install is the only fail-safe way.

0
Generally for alpha and beta releases of XenServer, there is no upgrade functionality built in or intended, but when a final release comes about, clearly there needs to be a way to do so. Hence for now, a clean install is the only fail-safe way.
Diogo on Friday, 02 October 2015 14:18

plus one for the ext4

0
plus one for the ext4
Guest - Scott on Monday, 05 October 2015 19:01

In one of the early Alpha releases it was mentioned that CIFS could be used for Virtual Machine storage I thought. I am not seeing that as an option in Beta 1 for when I try to create a new SR. CIFS is still there for a ISO library but not for VM Storage. Did I mis-read something or not read how to do this somewhere?

0
In one of the early Alpha releases it was mentioned that CIFS could be used for Virtual Machine storage I thought. I am not seeing that as an option in Beta 1 for when I try to create a new SR. CIFS is still there for a ISO library but not for VM Storage. Did I mis-read something or not read how to do this somewhere?
Guest - Scott on Monday, 05 October 2015 19:37

In a previous Alpha release it was mentioned that CIFS was an option for VM storage. When I go to create a new SR CIFS is an option for an ISO library but not for creating VM storage. Was this feature removed / pushed back to a later release?

0
In a previous Alpha release it was mentioned that CIFS was an option for VM storage. When I go to create a new SR CIFS is an option for an ISO library but not for creating VM storage. Was this feature removed / pushed back to a later release?
Guest - Sébastien RICCIO on Sunday, 11 October 2015 06:43

Some great improvements going on with XenServer. Congrats to the team.

However is there any plans for:
- vhdx support (to bypass the 2TB+ VDI size),
- support for clustered file systems such a CephFS (there was a tech preview long time ago for this but seems it went into a wall)
- block tracking (ability to mirror a VM on another xenserver host and keep it synched by regulary only transfer the changed blocks since last sync)

These features suggestions are often on the table but no real answer is provided :'(

Keep it going.
Cheers,
Sébastien

0
Some great improvements going on with XenServer. Congrats to the team. However is there any plans for: - vhdx support (to bypass the 2TB+ VDI size), - support for clustered file systems such a CephFS (there was a tech preview long time ago for this but seems it went into a wall) - block tracking (ability to mirror a VM on another xenserver host and keep it synched by regulary only transfer the changed blocks since last sync) These features suggestions are often on the table but no real answer is provided :'( Keep it going. Cheers, Sébastien
Guest - fbifido on Wednesday, 28 October 2015 18:48

1) How can I use my physical LightScribe burner, that's in my xenServer, use in a windows 7 VM, that's running on that server?

2) xenServer use qemu, qemu use seabios. Does xenServer used the qemu bios or its' own?

3) Can you do a blog on "How to Step-by-Step, setup a centos 7 x64 build environment for XenServer Dundee Beta 1" using the XenServer Dundee Beta 1 Source ISO.

4) Will XenServer Dundee, support vhdx, uefi, more refine vm-template-mods(like hyper-v VM v2.0, removal of older stuff, make vm boot faster), make DVD-burner(with its feature) 1-to-1 pass-through for a VM.

Thanks.

0
1) How can I use my physical LightScribe burner, that's in my xenServer, use in a windows 7 VM, that's running on that server? 2) xenServer use qemu, qemu use seabios. Does xenServer used the qemu bios or its' own? 3) Can you do a blog on "How to Step-by-Step, setup a centos 7 x64 build environment for XenServer Dundee Beta 1" using the XenServer Dundee Beta 1 Source ISO. 4) Will XenServer Dundee, support vhdx, uefi, more refine vm-template-mods(like hyper-v VM v2.0, removal of older stuff, make vm boot faster), make DVD-burner(with its feature) 1-to-1 pass-through for a VM. Thanks.
Tobias Kreidl on Monday, 02 November 2015 03:33

Adding VHDX support would be a huge benefit. +1

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Adding VHDX support would be a huge benefit. +1
Guest - Jeff Riechers on Tuesday, 10 November 2015 15:09

I was able to pass a pci attached Firewire port on my server into a VM by following the following guide.

http://ogris.de/howtos/xen-pci-passthrough.html

Passing a burner through might be difficult, as xen will see it as a storage device, and not a straight PCI connection. Better option would be to block a pci bus and pass it into a VM, then have that burner on that isolated bus.

0
I was able to pass a pci attached Firewire port on my server into a VM by following the following guide. http://ogris.de/howtos/xen-pci-passthrough.html Passing a burner through might be difficult, as xen will see it as a storage device, and not a straight PCI connection. Better option would be to block a pci bus and pass it into a VM, then have that burner on that isolated bus.
Guest - fbifido on Wednesday, 28 October 2015 20:56

Hi,
Is there a website/blog that shows the open-source components version that's use in the different xenServer?

What version of qemu using in XenServer Dundee ?

[ http://wiki.qemu.org/Features/VirtioSCSI - QEMU 2.4.0 ]
SCSI passthrough (tape, CD burning, ...)
## Tested use include: ## CD-ROM/DVD burning passthrough
## Tape passthrough
## 100s of LUNs (scalability)
## LUN hotplug (known to work with manual hotplug)

0
Hi, Is there a website/blog that shows the open-source components version that's use in the different xenServer? What version of qemu using in XenServer Dundee ? [ http://wiki.qemu.org/Features/VirtioSCSI - QEMU 2.4.0 ] SCSI passthrough (tape, CD burning, ...) ## Tested use include: ## CD-ROM/DVD burning passthrough ## Tape passthrough ## 100s of LUNs (scalability) ## LUN hotplug (known to work with manual hotplug)
Guest - Alan on Monday, 02 November 2015 01:43

I had the same question...

From the Source ISO:
kernel-3.10.87-434.382643
xen-4.6.0-2.0.0.709.31698
qemu-xen-2.0.2-2.32567

0
I had the same question... From the Source ISO: kernel-3.10.87-434.382643 xen-4.6.0-2.0.0.709.31698 qemu-xen-2.0.2-2.32567

About XenServer

XenServer is the leading open source virtualization platform, powered by the Xen Project hypervisor and the XAPI toolstack. It is used in the world's largest clouds and enterprises.
 
Commercial support for XenServer is available from Citrix.