Re: [Libvir] virsh start problem + patch
OK, I think that's a good explanation but I'll leave it to Dan to comment 'coz he wrote the code ... Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into Xen guests. http://et.redhat.com/~rjones/virt-p2v -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] [PATCH] Another Report error in virsh.c code.
On Tue, Mar 11, 2008 at 05:09:45PM +0900, S.Sakamoto wrote: BTW, I think another message is needed here to inform the internal error to user. For example, the migrate command shows the following message when desturi is missing: migrate: Missing desturi But it does not show the error-message even though migrateuri is missing because migrateuri is *not* a necessary option. I'm not sure I follow what is wrong. 'desturi' is required, so if missing we get an error. 'migrateuri' is not required, so there is no error if it is missing. And that's what the code does. So, I want to unify virsh.c with the following rules, - for necessary option show the message if error occur - for unnecessary option do not show the message even if error occur Do you have a patch or another way to explain this, because I'm afraid I don't follow what you mean. Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://et.redhat.com/~rjones/virt-top -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] [PATCH] Another Report error in virsh.c code.
On Tue, Mar 11, 2008 at 05:09:45PM +0900, S.Sakamoto wrote:
BTW, I think another message is needed here to inform the internal
error to user.
For example, the migrate command shows the following message when
desturi is missing:
migrate: Missing desturi
But it does not show the error-message even though migrateuri
is missing because migrateuri is *not* a necessary option.
I'm not sure I follow what is wrong. 'desturi' is required, so if
missing we get an error. 'migrateuri' is not required, so there is no
error if it is missing. And that's what the code does.
So, I want to unify virsh.c with the following rules,
- for necessary option
show the message if error occur
- for unnecessary option
do not show the message even if error occur
Do you have a patch or another way to explain this, because I'm afraid
I don't follow what you mean.
Sorry, My explanation is not enough...
What I meant to say was that I want to output to output error-message
at vcpupin as like migrate.
I wish it is unified as follows.
***migrate***
2225desturi = vshCommandOptString (cmd, desturi, found);
2226if (!found) {
2227vshError (ctl, FALSE, %s, _(migrate: Missing desturi));
2228goto done;
2229}
***vcpupin***
1731if (!(cpulist = vshCommandOptString(cmd, cpulist, NULL))) {
+ vshError (ctl, FALSE, %s, _(vcpupin: Missing cpulist));
1732virDomainFree(dom);
1733return FALSE;
1734}
Shigeki Sakamoto.
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Re: [Libvir] PATCH: Don't make connection read-only when non-root
On Mon, Mar 10, 2008 at 11:49:54AM +, Richard W.M. Jones wrote: On Sun, Mar 09, 2008 at 09:05:02PM +, Daniel P. Berrange wrote: The virsh commands has long forced the connection to be read-only if running as non-root. This is bogus because it is perfectly capable of authenticating full read-write connections as non-root since we gained kerberos/policykit support. The user can always use the explicit --readonly flag if they only want a read only connection Dan. Index: src/virsh.c === RCS file: /data/cvs/libvirt/src/virsh.c,v retrieving revision 1.135 diff -r1.135 virsh.c 6048,6054d6047 #ifndef __MINGW32__ /* Force a non-root, Xen connection to readonly */ if ((ctl-name == NULL || !strcasecmp(ctl-name, xen)) ctl-uid != 0) ctl-readonly = 1; #endif Yes. I was tempted to just remove this bogosity before but instead I just patched it out for Windows. okay Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ [EMAIL PROTECTED] | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/ -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] PATCH: Fix xen unified driver open logic
On Mon, Mar 10, 2008 at 07:09:36PM +, Daniel P. Berrange wrote: When adding PolicyKit support we disabled the proxy driver, but did not correctly fix up the Xen unified driver. The result is that it is still trying to run the proxy setuid helper which doesn't exist and thus it fails the open operation before the remote driver gets the opportunity to process the URI. I attempted to fix this by just disabling the proxy driver in the unified driver, but came to the conclusion the logic of the current code is just not flexible enough for what we need to be able todo these days. THe core problem is the 'for(;;)' loop iterating over the drivers - it already has several special cases in the loop body to skip drivers, or ignore errors and adding more special cases is making my mind hurt trying to trace the logic. So I have removed the loop, and encode the desired logic explicitly. The diff a little unpleasant to read, so to summarize the logic is thus: - If root only, try open the hypervisor driver - Failure to open is fatal, do not try other drivers hum, I'm not 100% sure of that, an old libvirt version might still be able to work though xend in face of an hypervisor change it can't handle, we had the problem for example with 0.4.0 on xen-3.2, there was side effects but it was basically working without hypervisor access... - Try to open the XenD driver - If XenD suceeds - If XenD 3.0.4, then open the XM driver for inactive domains - Try to open the XS driver = Failure to open is fatal if root - Else XenD fails -.If proxy is compiled in, try to open proxy = Failure to open is fatal This should result in one of the following combinations of drivers being activated: root: (HV + XenD + XS) root: (HV + XenD + XS + XM) root: (XenD + XS [+XM]) should still be allowed IMHO, non-root: (XenD) non-root: (XenD + XS) non-root: (proxy) If non-root, and the proxy is not compiled in, we'll hand off to the remote driver. Any other scenario will result in an explicit fail. okay except for the exception I sugegst to add back, Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ [EMAIL PROTECTED] | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/ -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
[Libvir] Accessing qemu from windows
Hi, I'm running virsh from linux machine with the URI qemu+tcp://user:password@ip/system From a linux machine (not the same that runs the libvirtd deamon) with libvirt 0.3.0, this URI allows me to connect. In the other hand, using the Virsh.exe (that comes with ocaml-libvirt-0.4.0.1.exehttp://libvirt.org/sources/ocaml/ocaml-libvirt-0.4.0.1.exe ) on Windows XP, I receive the error 'Virtualization error: libvirt: VIR_ERROR_NO_CONNECT: VIR_FROM_NONE: could not connect to qemu:///system?' Is it a known bug, or is it configuration problem on my server? Best Regards, Gabriel Kaufmann Software Engineer [EMAIL PROTECTED]mailto:[EMAIL PROTECTED] Ericom Software Tel (Dir): +972 2 591 1700 Ext 754 Tel (Main): +972 2 591 1700 http://www.ericom.com Access Done Right Empower Enterprise-Wide Access to Microsoft(r) Terminal Server, Virtual Desktops and Legacy Applications -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] Need Help on Error handling.
Thanks for the reply, I will see it and then will let you know. On Mon, Mar 10, 2008 at 6:23 PM, Chris Lalancette [EMAIL PROTECTED] wrote: Richard W.M. Jones wrote: On Sun, Mar 09, 2008 at 10:52:33PM +0530, Ajishrao.r wrote: Hi, I am using libvirt to manage, The Hypervisor, Can Any one Help me about handling error? My main questions are. --- What is Library level Error Handling? --- Any Example to use void virSetErrorFunc (void * userData,virErrorFunc http://libvirt.org/html/libvirt-virterror.html#virErrorFunc handler) I'm not aware of any example code which uses this. Actually, there is example code right in the libvirt source tree. In src/virsh.c, virSetErrorFunc() is used to set up the virshErrorHandler callback. I've used that as an example before for my own code :). Chris Lalancette -- ThanksRegards Ajeesh -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
[libvir] Could not connect to xend
Hi. When I tried to run virsh to connect to xen, I have got an error --- libvirt failed to open connection to xend. Here is output with DEBUG enabled. What kind of additional information do you need? [EMAIL PROTECTED] ~]# LIBVIRT_DEBUG=SPAM virsh DEBUG: libvirt.c: virInitialize (register drivers) DEBUG: libvirt.c: virConnectOpenAuth (name=(null), auth=0xb7ed79d8, flags=0) DEBUG: libvirt.c: do_open (Probed xen:///) DEBUG: libvirt.c: do_open (Using xen:/// as default URI, 1 hypervisor found) DEBUG: libvirt.c: do_open (name xen:/// to URI components: scheme xen opaque (null) authority (null) server (null) user (null) port 0 path / ) DEBUG: libvirt.c: do_open (trying driver 0 (Test) ...) DEBUG: libvirt.c: do_open (driver 0 Test returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 1 (QEMU) ...) DEBUG: libvirt.c: do_open (driver 1 QEMU returned DECLINED) DEBUG: libvirt.c: do_open (trying driver 2 (Xen) ...) DEBUG: xen_unified.c: xenUnifiedOpen (trying Xen sub-driver 0) DEBUG: xen_unified.c: xenUnifiedOpen (Xen sub-driver 0 open ok ) DEBUG: xen_unified.c: xenUnifiedOpen (trying Xen sub-driver 2) libvir: Xen Daemon error : internal error failed to connect to xend libvir: Xen Daemon error : internal error failed to connect to xend DEBUG: xen_unified.c: xenUnifiedOpen (Xen sub-driver 2 open failed ) DEBUG: libvirt.c: do_open (driver 2 Xen returned ERROR) DEBUG: hash.c: virUnrefConnect (unref connection 0x807bf88 xen:/// 1) DEBUG: hash.c: virReleaseConnect (release connection 0x807bf88 xen:///) error: failed to connect to the hypervisor -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvir] Could not connect to xend
On Tue, Mar 11, 2008 at 05:23:24PM +0300, Anton Protopopov wrote: Hi. When I tried to run virsh to connect to xen, I have got an error --- libvirt failed to open connection to xend. Here is output with DEBUG enabled. What kind of additional information do you need? [EMAIL PROTECTED] ~]# LIBVIRT_DEBUG=SPAM virsh [snip] DEBUG: libvirt.c: do_open (trying driver 2 (Xen) ...) DEBUG: xen_unified.c: xenUnifiedOpen (trying Xen sub-driver 0) DEBUG: xen_unified.c: xenUnifiedOpen (Xen sub-driver 0 open ok ) DEBUG: xen_unified.c: xenUnifiedOpen (trying Xen sub-driver 2) libvir: Xen Daemon error : internal error failed to connect to xend libvir: Xen Daemon error : internal error failed to connect to xend DEBUG: xen_unified.c: xenUnifiedOpen (Xen sub-driver 2 open failed ) DEBUG: libvirt.c: do_open (driver 2 Xen returned ERROR) So XenD driver failed - check - That XenD is running - That /etc/xen/xend-config.sxp has '(xend-unix-server yes)' set - That the XenD process has /var/lib/xend/xend-socket open (use lsof) Dan. -- |: Red Hat, Engineering, Boston -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :| -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] [PATCH] Another Report error in virsh.c code.
On Tue, Mar 11, 2008 at 07:19:57PM +0900, S.Sakamoto wrote:
I wish it is unified as follows.
***migrate***
2225desturi = vshCommandOptString (cmd, desturi, found);
2226if (!found) {
2227vshError (ctl, FALSE, %s, _(migrate: Missing desturi));
2228goto done;
2229}
***vcpupin***
1731if (!(cpulist = vshCommandOptString(cmd, cpulist, NULL))) {
+ vshError (ctl, FALSE, %s, _(vcpupin: Missing cpulist));
1732virDomainFree(dom);
1733return FALSE;
1734}
So the problem is just the text in the error message? ie. Instead
of:
$ virsh vcpupin
error: command 'vcpupin' requires domain option
error: command 'vcpupin' requires vcpu option
error: command 'vcpupin' requires cpulist option
you want it to print a different message, as in:
vcpupin: Missing cpulist
?
Rich.
--
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powerful monitoring features, net stats, disk stats, logging, etc.
http://et.redhat.com/~rjones/virt-top
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Re: [Libvir] Snapshots for Xen and KVM
On Tue, Mar 11, 2008 at 12:54:37PM +0200, Gabriel Kaufmann wrote: Does anyone knows if Xen and KVM support snapshots (regardless if Libvirt provides the API for them). It's currently on the Xen to-do list, but apart from some research papers I'm not aware of them implementing it. Perhaps recently. Checkpointing is tricky to get right because you have to take a snapshot of the memory and disk at exactly the same moment. Note that neither Xen's live migration nor the domain save features are real checkpoints, because they both only consider the memory. If yes, will libvirt add API for it? If it's supported, then why not. Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into Xen guests. http://et.redhat.com/~rjones/virt-p2v -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] Accessing qemu from windows
On Tue, Mar 11, 2008 at 01:00:23PM +0200, Gabriel Kaufmann wrote: I'm running virsh from linux machine with the URI qemu+tcp://user:password@ip/system From a linux machine (not the same that runs the libvirtd deamon) with libvirt 0.3.0, this URI allows me to connect. In the other hand, using the Virsh.exe (that comes with ocaml-libvirt-0.4.0.1.exehttp://libvirt.org/sources/ocaml/ocaml-libvirt-0.4.0.1.exe ) on Windows XP, I receive the error 'Virtualization error: libvirt: VIR_ERROR_NO_CONNECT: VIR_FROM_NONE: could not connect to qemu:///system?' Is it a known bug, or is it configuration problem on my server? I suspect a bug actually. I only tested remote Xen and remote test drivers, not remote QEMU. Can you find out if it's actually trying to make a remote TCP connection at all? Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://et.redhat.com/~rjones/virt-top -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
[Libvir] virsh list command of libvirt consumes a lot of CPU in the domain-0
Hi all, I know that this is not a libvirt issue but this badly impacts libvirt usage. Is anyone aware of any status on this issue ? Daniel ? Here is some history I could get from the libvirt mailing list : * October 12, 2006 (Daniel Berrange). I've been trying to track down just why talking to XenD is resulting in so much CPU time being comsumed by both xend xenstored. As a test case, I'm running 'virsh dominfo demo' which results in a single HTTP request to Xend to fetch domain info, eg 'GET /xend/domains/demo' Run this in a tight loop I'll see xenstored taking 50% CPU, and XenD taking another 11% PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2647 root 16 0 6188 840 464 R 52 0.0 0:55.04 xenstored 11600 root 18 0 259m 7568 1516 S 11 0.2 0:04.53 python Its not surprising that xend is consuming time since we are making many requests per second, but for an operation which is only doing reads it having so much time attributed to xenstored seems very excessive. So I ran oprofile collected some data about xenstored: CPU: AMD64 processors, speed 2211.33 MHz (estimated) Counted CPU_CLK_UNHALTED events (Cycles outside of halt state) with a unit mask of 0x00 (No unit mask) count 10 samples % image name symbol name 347226 45.9445 ext3 (no symbols) 264664 35.0200 jbd (no symbols) 31778 4.2048 libc-2.5.so memset 10763 1.4241 xenstored main 8884 1.1755 libc-2.5.so _int_malloc 7053 0.9332 libc-2.5.so vfprintf 4264 0.5642 xenstored initialize_set So almost 80% of xenstored's CPU time is attributed to ext3 journalling modules, suggesting xenstored is doing alot of disk I/O. strace()'ing the xenstored process shows the only file it is opening is: # strace -p 2647 -e trace=open,rename,unlink Process 2647 attached - interrupt to quit open(/var/lib/xenstored/tdb.0x62aa80, O_WRONLY|O_CREAT|O_TRUNC, 0640) = 13 open(/var/lib/xenstored/tdb.0x62aa80, O_RDWR) = 15 rename(/var/lib/xenstored/tdb.0x62aa80, /var/lib/xenstored/tdb) = 0 unlink(/var/lib/xenstored/tdb.0x62aa80) = -1 ENOENT (No such file or directory) open(/var/lib/xenstored/tdb.0x62b2b0, O_WRONLY|O_CREAT|O_TRUNC, 0640) = 13 open(/var/lib/xenstored/tdb.0x62b2b0, O_RDWR) = 14 rename(/var/lib/xenstored/tdb.0x62b2b0, /var/lib/xenstored/tdb) = 0 unlink(/var/lib/xenstored/tdb.0x62b2b0) = -1 ENOENT (No such file or directory) ... So basically it is repeatedly copying its persistent TBD database over and over again. The TDB on this system is 128 KB in size and each individual HTTP GET on /xend/domain/demo is resulting in 16 copies being made. Do the maths - 128 * 16 == 2 MB of reads, and 2 MB of writes - for a single read in XenD. Now if I monitor the status of 20 domains, once per second that's causing 40 MB of writes 40 MB of reads every second which is utterly ridiculous completely non scalable for enterprise deployment :-( There's two problems I see here: 1. Why the need for xenstored to be doing any of this I/O in the first place? If the DB needs to be kept on disk at all, it really needs to have a much saner update/transactional model to only update bits which actually change, rather than re-creating the entire DB on every transaction. But it strikes me that the DB could potentially be kept entirely in memory removing the disk I/O completely. Sure yyou wouldn't be able to restart the daemon then, but even today you can't restart xenstored expect things to still be working. 2. Why does XenD create sooo many transactions in XenStored for a read op ? Having instrumented Xend it sems that the root cause of the problem is the xen.xend.xenstore.xstransact class. This alllows one to start a transaction, do a bunch of reads/writes then commit the transaction. At the same time though it has a bunch of static 'convenience' methods for read write which will implicitly start commit a transaction. Well 90% of the code in XenD seems to be using these 'convenience' methods instead of explicitly starting a transaction to cover a piece of work - the result is a simple GET causes 16 transactions and an 'xm create' results in 80 transactions. These convenience methods are utterly destroying performance. Clearly we can't address these for 3.0.3, but I think both of these areas need serious work in 3.0.4 if we want a scalable control plane in Dom0. Fixing the XenD bit looks particularly hard because any single method using the convenience xenstored read functions can be called under many different contexts, so of which needs transactions, others which don't. It ought to be possible to trace back all the calls make it possible to pass explicit xstransct objects into all calls then kill off the convenience methods. * Answer, same day (October 12, 2006) Yes, xenstored is very simple minded in many respects. We will certainly be improving this during 3.0.4 development -- I think we can get the costs down very significantly for commonplace operations without enormous effort. * Avril 25, 2007 (Daniel Berrange) Xen 3.0.3 has a
Re: [Libvir] Accessing qemu from windows
On Tue, Mar 11, 2008 at 06:00:31PM +0200, Gabriel Kaufmann wrote: I'm sure it actually makes a remote TCP connection since on the server side I get the error: 'libvir: error : could not connect to qemu:///system?' It actually prints this out on the server side? Can you run the server with the --verbose option, you'll get a lot more detail about what is happening. Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into Xen guests. http://et.redhat.com/~rjones/virt-p2v -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] Snapshots for Xen and KVM
Is there a means of snapshotting before you start up xen, and then reverting after you shut it down? -- bk Richard W.M. Jones wrote: On Tue, Mar 11, 2008 at 12:54:37PM +0200, Gabriel Kaufmann wrote: Does anyone knows if Xen and KVM support snapshots (regardless if Libvirt provides the API for them). It's currently on the Xen to-do list, but apart from some research papers I'm not aware of them implementing it. Perhaps recently. Checkpointing is tricky to get right because you have to take a snapshot of the memory and disk at exactly the same moment. Note that neither Xen's live migration nor the domain save features are real checkpoints, because they both only consider the memory. If yes, will libvirt add API for it? If it's supported, then why not. Rich. -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] virsh start problem + patch
On Tue, Mar 11, 2008 at 06:57:33AM +0100, Toth Istvan wrote: # virsh list --all Id Name State -- 0 Domain-0 running - windows-xen shut off - windows-xen2 no state # xm list NameID Mem VCPUs State Time(s) Domain-0 0 3489 4 r- 853.6 windows-xen 1 512 0 -b-s-d 39.4 windows-xen2 4 512 0 -- 22.5 The windows-xen, and windows-xen2 domains were installed the very same way, except I've had a Dom0 reboot since I've installed windows-xen, so xen has had the opportunity to sort it's state out, whil the windows-xen2 domain is a fresh install. Starting and stopping (by xm) a freshly installed windows hvm domain does not sort out the state, only a Dom0 reboot (or a xend restart) does. I have attached the output of xm list --long command. This shows that it is all XenD related - inactive domains should *not* have a 'domid' or 'state' field set in the 'xm list --long' output. In both your windows-xen windows-xen2 VM, these fields are incorrectly present. This problem indeed does look like a Xend bug, but it turns out that it does not actually affect virsh. (It does affect virt-manager, as I've written to the other list) The other problem is I am pretty sure, a virsh logic bug, and is independent of the first one. No, it is again a Xen bug. Inactive domains are *mandated* to have a domain ID of -1. They do not exist in the hypervisor anymore and thus have no domain ID associated with them. If XenD is not clearing the domain ID properly this is a XenD problem. That all said, we may need to workaround this XenD brokenness in the libirt XenD driver. Working around it in virsh is the wrong place. and I get this: ./virsh start windows-xen warnings error: Domain is already active virDomainGetID(dom) returns 1 ./virsh start windows-xen2 warnings error: Domain is already active virDomainGetID(dom) returns 3 so virDomainGetID() does not return -1, but returns the actual xen domain id of the managed, but inactive xen domain, and I believe this is what it should do, as it's job is not to tell us about the state of the domain, but to tell the id of the domain, regardles of its state. No. Inactive domains are mandated to have an ID of -1. Dan. -- |: Red Hat, Engineering, Boston -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :| -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [Libvir] Snapshots for Xen and KVM
On Tue, Mar 11, 2008 at 03:43:51PM +, Richard W.M. Jones wrote: On Tue, Mar 11, 2008 at 12:54:37PM +0200, Gabriel Kaufmann wrote: Does anyone knows if Xen and KVM support snapshots (regardless if Libvirt provides the API for them). It's currently on the Xen to-do list, but apart from some research papers I'm not aware of them implementing it. Perhaps recently. Checkpointing is tricky to get right because you have to take a snapshot of the memory and disk at exactly the same moment. Note that neither Xen's live migration nor the domain save features are real checkpoints, because they both only consider the memory. Why would Xen itself be at all concerned with snapshotting the disk? AIUI, there's hooks in xend so you just plug in your disk snapshotting (ZFS, LVM, vmdk, whatever) to that. regards john -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
