When the XenStore tdb lives persistently and is not cleared between host reboots, Xend (version 3.4 and 4.1) re-creates the domain information located in XenStore below /vm/$UUID. (According to the xen-3.2-commit hg265950e3df69 to fix a problem when locally migrating a domain to the host itself.) When doing so a version number is added to the UUID separated by one dash, which confuses xenStoreDomainIntroduced(): It iterates over all domains and tries to lookup all inactive domains using xenStoreDomainGetUUID(), which fails if the running domain is renamed: virUUIDParse() fails to parse the versioned UUID and the domain is flagged as missing. When this happens the function delays .2s and re-tries 20 times again, multiplied by the number of renamed VMs. 14:48:38.878: 4285: debug : xenStoreDomainIntroduced:1354 : Some domains were missing, trying again This adds a significant delay: # time virsh list >/dev/null real 0m6.529s # xenstore-list /vm 00000000-0000-0000-0000-000000000000 00000000-0000-0000-0000-000000000000-1 00000000-0000-0000-0000-000000000000-2 00000000-0000-0000-0000-000000000000-3 00000000-0000-0000-0000-000000000000-4 00000000-0000-0000-0000-000000000000-5 7c06121e-90c3-93d4-0126-50481d485cca 00000000-0000-0000-0000-000000000000-6 00000000-0000-0000-0000-000000000000-7 144ad19d-dfb4-2f80-8045-09196bb8784f 00000000-0000-0000-0000-000000000000-8 144ad19d-dfb4-2f80-8045-09196bb8784f-1 00000000-0000-0000-0000-000000000000-9 00000000-0000-0000-0000-000000000000-10 00000000-0000-0000-0000-000000000000-11 00000000-0000-0000-0000-000000000000-12 00000000-0000-0000-0000-000000000000-13 00000000-0000-0000-0000-000000000000-14 144ad19d-dfb4-2f80-8045-09196bb8784f-2 00000000-0000-0000-0000-000000000000-15 144ad19d-dfb4-2f80-8045-09196bb8784f-3 00000000-0000-0000-0000-000000000000-16 The patch adds truncation of the UUID as read from the XenStore path before passing it to virUUIDParse(). The same issue is reported at <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=666135> Signed-off-by: Philipp Hahn <hahn(a)univention.de&gt; --- src/xen/xs_internal.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/src/xen/xs_internal.c b/src/xen/xs_internal.c index e56d1a4..cdaef17 100644 --- a/src/xen/xs_internal.c +++ b/src/xen/xs_internal.c @@ -1115,8 +1115,11 @@ int xenStoreDomainGetUUID(virConnectPtr conn, snprintf(prop, 199, "/local/domain/%d/vm", id); prop[199] = 0; /* This will return something like - * /vm/00000000-0000-0000-0000-000000000000 */ + * /vm/00000000-0000-0000-0000-000000000000[-*] */ uuidstr = xs_read(priv->xshandle, 0, prop, &len); + /* Strip optional version suffix when VM was renamed */ + if (len > 40) /* strlen('/vm/') + VIR_UUID_STRING_BUFLEN - sizeof('\0') */ + uuidstr[40] = '\0'; /* remove "/vm/" */ ret = virUUIDParse(uuidstr + 4, uuid); -- 1.7.1