Hello, I''m new to Xen but not to Linux, I just bought a 10 blade dell chassis (10 x 2 x quad core Xeon x 8 GB) and a 4.5 TB iSCSI SAN. I''ll be running RHEL 5 on all of the blades and I plan on running 4 Xen children on each blade, Most Xen children will para-virt RHEL but I''ll have a couple Win2k3 servers. The machines will be running standard ISP type services (DNS,LDAP,RADIUS,Plesk, SMTP,POP3,IMAP, MySQL) I have couple questions: 1). Is RHEL & Xen ready for prime time? (is it production ready, will I sleep at night?) 2). Each Xen instance will have a LUN on the iSCSI. Should I connect the LUN on Domain0 and then have the DomU load it or should I have each DomU run iSCSI directly with the SAN? I want to enable live migrate between the blades. 3). Are there any pre-built Xen ''Appliances'' for common things like DNS resolvers? 4). Should I use rsync between the blades to syn the xen configs to I can live migrate guest machines between the blades? My primary concern is #1, if it isn''t stable I''ll look to VMWare or Virtuozzo. I have a machine running Virtuozzo already and it works ok, Would rather run something open though, Linux has served me well the last 17 years. -Matt _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
What is the expected compatibility of domU image versions on various
dom0 systems.
dom0 3.0.4
Can it run a HVM domU that was created on a 3.2 dom0
Can it run a PV domU that was created on a 3.2 dom0
dom0 3.2
Can it run a HVM domU that was created on a 3.0.4 dom0
Can it run a PV domU that was created on a 3.0.4 dom0
Is there a compatibility chart somewhere?
Thanks in advance
Pat
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>1). Is RHEL & Xen ready for prime time? (is it production ready, will >I sleep at night?)>2). Each Xen instance will have a LUN on the iSCSI. Should I connect >the LUN on Domain0 and then have the DomU load it or should I have >each DomU run iSCSI directly with the SAN? I want to enable live >migrate between the blades. > >3). Are there any pre-built Xen ''Appliances'' for common things like >DNS resolvers? > >4). Should I use rsync between the blades to syn the xen configs to I >can live migrate guest machines between the blades? > >My primary concern is #1, if it isn''t stable I''ll look to VMWare or >Virtuozzo. I have a machine running Virtuozzo already and it works >ok, Would rather run something open though, Linux has served me well >the last 17 years. > >-MattI too am curious about these exact questions. I am new to both Linux and Xen though. I can say I have used vmware for these same platforms in your exact scenario with an iSCSI san but am wanting to move to Xen for cost reasons. If you find the answers to these questions off list, kindly update the thread as I am anxiously awaiting direction from experienced users myself :) jlc _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Joseph L. Casale wrote:>> 1). Is RHEL & Xen ready for prime time? (is it production ready, will >> I sleep at night?) >> > > >> 2). Each Xen instance will have a LUN on the iSCSI. Should I connect >> the LUN on Domain0 and then have the DomU load it or should I have >> each DomU run iSCSI directly with the SAN? I want to enable live >> migrate between the blades. >> >> 3). Are there any pre-built Xen ''Appliances'' for common things like >> DNS resolvers? >> >> 4). Should I use rsync between the blades to syn the xen configs to I >> can live migrate guest machines between the blades? >> >> My primary concern is #1, if it isn''t stable I''ll look to VMWare or >> Virtuozzo. I have a machine running Virtuozzo already and it works >> ok, Would rather run something open though, Linux has served me well >> the last 17 years. >> >> -Matt >> > > > I too am curious about these exact questions. I am new to both Linux and Xen though. I can say I have used vmware for these same platforms in your exact scenario with an iSCSI san but am wanting to move to Xen for cost reasons. If you find the answers to these questions off list, kindly update the thread as I am anxiously awaiting direction from experienced users myself :) >I''ve been using RHEL 5 for Xen servers in production. I don''t live-migrate right now because I''m not using (or rather, didn''t use in my last contract) network based Xen images, but I did keep the configurations distributed on all the servers for load balancing and restoration from backup. I''m not aware of Xen appliances, but for DNS servers you can use a stripped down RHEL with bind and nscd pretty trivially. Stripping an RHEL system to bare bones is a pain due to the dependency hel and massive overpopulation of the "Basic" installation. Frankly, a bare-bones install doesn''t even need Perl, but try teaching the RPM dependency tree not do that. And try telling an RHEL installer that no, you don''t *WANT* NIS and PCMCIA and Bluetooth and a bunch of other silly things in a Xen environment. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mark Williamson
2008-Jan-02 18:49 UTC
Re: [Xen-users] Xen domU version compatibility questions
> What is the expected compatibility of domU image versions on various > dom0 systems.Hmmm. Slightly tricky question...> dom0 3.0.4 > Can it run a HVM domU that was created on a 3.2 dom0I''d guess the safe answer here is probably "maybe"... The potential problem I see is where the virtual hardware features differ between different Xen versions. I don''t know of any showstoppers for doing this with either Windows or Linux guests (whereas if you used an older Xen, say 3.0.3, then HVM ACPI wasn''t available and that''s likely to cause more problems). But I''m not comfortable to assert it will work, because I don''t know enough about the HVM support.> Can it run a PV domU that was created on a 3.2 dom0In general compatibility is only guaranteed with *older* guests. In practice, XenSource''s XenLinux contains some compatibility options enabling it to fallback to old APIs to run on older Xens, so these may run on quite old Xen releases. So for one of these kernels, the guest will definitely run on the old dom0. I don''t even know if any compatibility code is required for a 3.2 domU to run on 3.0.4 - there may not have been any significant API changes...> dom0 3.2 > Can it run a HVM domU that was created on a 3.0.4 dom0Again, I would guess this would probably work and I don''t know of any showstoppers. The potential problems again revolve around any changes in the virtual hardware that might upset the guest. I suspect this might work OK, but I''m not going to assert it definitely will.> Can it run a PV domU that was created on a 3.0.4 dom0Yes, definitely, this compatibility direction (older guest on newer Xen) is always intended to work.> Is there a compatibility chart somewhere?Maybe on the wiki? I''ve certainly posted related information on the list before but I''ve never actually gone and published it somewhere central. Cheers, Mark -- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hello, Happy New Year everybody. I''ve been coding during much of the winter break, whilst stuck indoors with bronchitis, but I''m now trying to catch up on my mailbox a bit!> >> 1). Is RHEL & Xen ready for prime time? (is it production ready, will > >> I sleep at night?)Well, RedHat seem to think so ;-) It rather depends what you''re doing though. For instance, Windows guests are only supported since RHEL 5.1 - and those won''t perform fantastically unless you get the driver pack that Redhat are going to (or have already?) release. I''m not sure if they officially support Live Migration or some of the other whizzy features.> >> 2). Each Xen instance will have a LUN on the iSCSI. Should I connect > >> the LUN on Domain0 and then have the DomU load it or should I have > >> each DomU run iSCSI directly with the SAN? I want to enable live > >> migrate between the blades.I always think it''s nicer to abstract away details of storage from guests as much as possible and handle them all in dom0 - that way domU just sees there''s a "VBD" and doesn''t need to know if you change things. It also avoids having to do funny things to make iSCSI root work. There are probably good arguments for exposing iSCSI to the guests too, so it depends on your preference, I guess.> >> 3). Are there any pre-built Xen ''Appliances'' for common things like > >> DNS resolvers?rpath distribute a whole load of appliances, with options for Xen support as well as support for other VMMs and native install. These are fairly polished: download image, boot guest, DHCP automatically, prompted for configuration info, further config via web interface. jailtime.org and xen-get.org both have some images but some of these may well be a bit out of date.> >> 4). Should I use rsync between the blades to syn the xen configs to I > >> can live migrate guest machines between the blades? > >> > >> My primary concern is #1, if it isn''t stable I''ll look to VMWare or > >> Virtuozzo. I have a machine running Virtuozzo already and it works > >> ok, Would rather run something open though, Linux has served me well > >> the last 17 years.If you want something open and you like Virtuozze, there''s always OpenVZ? Also, you''ve got the option of various other virtualisers (KVM, the free-beer VMware Server) at no cost, which you might also find suitable. Finally, there''s a range of different Xen-based hypervisor appliances of varying levels of open / closed coming onto the market from Novell, XenSource/Citrix, Virtual Iron, Oracle, Sun, etc.> I''ve been using RHEL 5 for Xen servers in production. I don''t > live-migrate right now because I''m not using (or rather, didn''t use in > my last contract) network based Xen images, but I did keep the > configurations distributed on all the servers for load balancing and > restoration from backup.Even doing non-live migration - or shutdown on one machine, then restart on another - should help make life easier.> I''m not aware of Xen appliances, but for DNS servers you can use a > stripped down RHEL with bind and nscd pretty trivially. Stripping an > RHEL system to bare bones is a pain due to the dependency hel and > massive overpopulation of the "Basic" installation. Frankly, a > bare-bones install doesn''t even need Perl, but try teaching the RPM > dependency tree not do that. And try telling an RHEL installer that no, > you don''t *WANT* NIS and PCMCIA and Bluetooth and a bunch of other silly > things in a Xen environment.I wonder if anybody has put together a script to "barebonesify" RHEL / CentOS - that would be quite useful! Cheers, Mark -- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Wednesday 02 January 2008 01:49:08 pm Mark Williamson wrote:> I don''t know of any showstoppers for doing this with either Windows or > Linux guests (whereas if you used an older Xen, say 3.0.3, then HVM ACPI > wasn''t available and that''s likely to cause more problems).I''ve always thought power save was an acpi function but my Windows hvm guest doesn''t provide a power settings button on the screensaver tab of Explorer''s Properties dialog. (fc8 compiles xen.gz from 3.1.0 rc7 sources, but recently updated the tools to 3.1.2) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mark Williamson
2008-Jan-03 02:14 UTC
Re: [Xen-users] Xen domU version compatibility questions
> > I don''t know of any showstoppers for doing this with either Windows or > > Linux guests (whereas if you used an older Xen, say 3.0.3, then HVM ACPI > > wasn''t available and that''s likely to cause more problems). > > I''ve always thought power save was an acpi function but my Windows hvm > guest doesn''t provide a power settings button on the screensaver tab of > Explorer''s Properties dialog. (fc8 compiles xen.gz from 3.1.0 rc7 sources, > but recently updated the tools to 3.1.2)ACPI is involved in powersaving stuff but it''s used for a load of other things as well. It''s used to set up SMP and interrupts, to support those funny extra buttons you get on laptops, to get information about docking stations ... It''s actually quite a scary and complex piece of technology and I don''t understand it well at all. I seem to recall that Windows doesn''t make it easy to switch on / off ACPI support, hence switching to an older Xen version that doesn''t have it having installed Windows on a newer version is likely to upset things. Not an issue for normal use. Cheers, Mark -- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users