From 440838472d860224a94a77ca1f2c100df6c3ca77 Mon Sep 17 00:00:00 2001 From: Jiri Denemark Date: Fri, 8 Sep 2017 21:31:29 +0200 Subject: [PATCH] virsh: Enhance documentation of --rdma-pin-all option https://bugzilla.redhat.com/show_bug.cgi?id=1373783 Signed-off-by: Jiri Denemark Reviewed-by: Pavel Hrdina --- tools/virsh.pod | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/virsh.pod b/tools/virsh.pod index 4331c76fc7..576f0c1228 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -1767,7 +1767,13 @@ periodically increased by I. I<--rdma-pin-all> can be used with RDMA migration (i.e., when I starts with rdma://) to tell the hypervisor to pin all domain's memory at once -before migration starts rather than letting it pin memory pages as needed. +before migration starts rather than letting it pin memory pages as needed. For +QEMU/KVM this requires hard_limit memory tuning element (in the domain XML) to +be used and set to the maximum memory configured for the domain plus any memory +consumed by the QEMU process itself. Beware of setting the memory limit too +high (and thus allowing the domain to lock most of the host's memory). Doing so +may be dangerous to both the domain and the host itself since the host's kernel +may run out of memory. B: Individual hypervisors usually do not support all possible types of migration. For example, QEMU does not support direct migration.