-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I''m new to Xen so please bear with my basic questions. I use Debian Kernels with add-on patches applied to it. (Bootsplash, SKAS, debianlogo, kdb, swsusp et cetera). I want to try Xen too. I looked into Xen Source tarball which contains a "mkbuildtree" shell script which adds xen tree to my patched kernel. My questions: 1) If I patch my kernel with Xen, will I be compromising on any of the other features that I''ve patched ? (Namely UML and swsusp. I use UML a lot) 2) So when I boot with a Xen kernel, the OS it boots into is dom0 which simply is my normal OS. Right ? 3) If I''m correct about Question 2 then, "when only using dom0, does it add any virtualization overhead to the host OS i.e. dom0 ? Or does it simply function as a normal Linux Kernel with Xen features not being in use ? " Thanks, Ritesh - -- Ritesh Raj Sarraf RESEARCHUT -- http://www.researchut.com "Stealing logic from one person is plagiarism, stealing from many is research." "Necessity is the mother of invention." -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEGx0z4Rhi6gTxMLwRAoVAAKCalD3jQBHgFdqTs2qR1AhBgk90cACgo5te G5T2EEfC238mn5mZKHXIntQ=EDSo -----END PGP SIGNATURE----- _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Can someone please shed some light on it ? Thanks, Ritesh Ritesh Raj Sarraf on Saturday 18 Mar 2006 02:03 wrote:> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi, > > I''m new to Xen so please bear with my basic questions. > > I use Debian Kernels with add-on patches applied to it. (Bootsplash, SKAS, > debianlogo, kdb, swsusp et cetera). > > I want to try Xen too. I looked into Xen Source tarball which contains a > "mkbuildtree" shell script which adds xen tree to my patched kernel. > > My questions: > > 1) If I patch my kernel with Xen, will I be compromising on any of the > other features that I''ve patched ? (Namely UML and swsusp. I use UML a > lot) > > 2) So when I boot with a Xen kernel, the OS it boots into is dom0 which > simply is my normal OS. Right ? > > 3) If I''m correct about Question 2 then, "when only using dom0, does it > add any virtualization overhead to the host OS i.e. dom0 ? Or does it > simply function as a normal Linux Kernel with Xen features not being in > use ? " >- -- Ritesh Raj Sarraf RESEARCHUT -- http://www.researchut.com "Necessity is the mother of invention." "Stealing logic from one person is plagiarism, stealing from many is research." -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEHT4/4Rhi6gTxMLwRAj5fAJwJhOxHRHrn8ncgDawBKYZLGtiv6wCgs2J2 lfkPhioGvRmThj3rYRWErXY=VQBO -----END PGP SIGNATURE----- _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Ritesh Raj Sarraf wrote:> 1) If I patch my kernel with Xen, will I be compromising on any of > the other > features that I''ve patched ? (Namely UML and swsusp. I use UML a lot)swsusp: Software Suspend http://sourceforge.net/projects/swsusp It''s unlikely this will work with Xen. This would undoubtedly require a patch into the Xen hypervisor to save & restore the other domains. Even if you were only running dom0, this might still not work. UML: User Mode Linux Interesting. UML is a technology which accomplishes some of the same goals as Xen. Xen can run multiple instances of Linux, like UML. So from that stand point, you''ll get many of the same features as UML. However, Xen can also run other operating systems: FreeBSD, NetBSD, Minix (in theory), Windows XP (with the right processor), etc. It''s my opinion that Xen is a superset of the functionality one can get with UML. If UML is important to you, I encourage you to continue learning about the virtues of Xen. The answer to the question: "will I be compromising on any of the other features?" is yes.> 2) So when I boot with a Xen kernel, the OS it boots into is dom0 > which > simply is my normal OS. Right ?More or less. However, the Linux running as dom0 will likely not be the same -kernel- image that you are currently running. But, it will be Linux and it will see your current file systems, devices (assuming your configuration files are suitably identical), etc.> 3) If I''m correct about Question 2 then, "when only using dom0, > does it add > any virtualization overhead to the host OS i.e. dom0 ? Or does it > simply > function as a normal Linux Kernel with Xen features not being in > use ? "It does add overhead to use Xen even with only dom0 present, but they''re minimal. It''s likely you won''t notice them. Various presentations indicate the performance impact is as low as 3%. -- Randy _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Randy Thelen on Monday 20 Mar 2006 12:45 wrote:> Ritesh Raj Sarraf wrote: > >> 1) If I patch my kernel with Xen, will I be compromising on any of >> the other >> features that I''ve patched ? (Namely UML and swsusp. I use UML a lot) > > swsusp: Software Suspend > http://sourceforge.net/projects/swsusp > > It''s unlikely this will work with Xen. This would undoubtedly > require a patch into the Xen hypervisor to save & restore the other > domains. Even if you were only running dom0, this might still not work. > > UML: User Mode Linux > Interesting. UML is a technology which accomplishes some of the same > goals as Xen. Xen can run multiple instances of Linux, like UML. So > from that stand point, you''ll get many of the same features as UML. > However, Xen can also run other operating systems: FreeBSD, NetBSD, > Minix (in theory), Windows XP (with the right processor), etc. >Thanks for replying. Basically I''m looking to build the kernel with all support. I want a kernel with Xen support which I can use for UML too when I''m not running any other domU (other OSes in Xen) want. Right now my kernels are patched with UML but I don''t use UML always. I use it only when I want, else my machine runs as a normal machine.> It''s my opinion that Xen is a superset of the functionality one can > get with UML. If UML is important to you, I encourage you to > continue learning about the virtues of Xen. > > The answer to the question: "will I be compromising on any of the > other features?" is yes. > >> 2) So when I boot with a Xen kernel, the OS it boots into is dom0 >> which >> simply is my normal OS. Right ? > > More or less. However, the Linux running as dom0 will likely not be > the same -kernel- image that you are currently running. But, it will > be Linux and it will see your current file systems, devices (assuming > your configuration files are suitably identical), etc. >So basically it''d be the same kernel with Xen features?>> 3) If I''m correct about Question 2 then, "when only using dom0, >> does it add >> any virtualization overhead to the host OS i.e. dom0 ? Or does it >> simply >> function as a normal Linux Kernel with Xen features not being in >> use ? " > > It does add overhead to use Xen even with only dom0 present, but > they''re minimal. It''s likely you won''t notice them. Various > presentations indicate the performance impact is as low as 3%. > > -- RandyThat''s good. 3% overhead is worth trying Xen. :-) Thanks, Ritesh - -- Ritesh Raj Sarraf RESEARCHUT -- http://www.researchut.com "Necessity is the mother of invention." "Stealing logic from one person is plagiarism, stealing from many is research." -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) iD8DBQFEHl0R4Rhi6gTxMLwRAplEAJ98LEtw/KkIvbNvcLCE3yM5oOnRuACdGwvE kp1Wy7l1uEMa/OUufIDJB+c=p/tT -----END PGP SIGNATURE----- _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users