On 03.07.2012 15:05, address@hidden wrote:
From: Wenchao Xia<address@hidden>
Qemu system emulator reports only fails that make people confused
about why, when it is invoked with nbd block device tring to connect
qemu-nbd server. In fact qemu will try connect server for several
times but server only accept one connect by default.
I paid some times to find out why it fails. This patch add special
text to explain how to use it in such case.
Signed-off-by: Wenchao Xia<address@hidden>
---
qemu-nbd.texi | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 6955d90..014040a 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -44,6 +44,12 @@ Export QEMU disk image using NBD protocol.
display this help and exit
@item -V, --version
output version information and exit
+
+ Note: When qemu-nbd was used to export a disk that would be used by QEMU
+block device, -t or --persistent must be set for that QEMU nbd client would try
+connect more than one time. For eg:
+ qemu-nbd ./simple.img -p 10809 -t
+ qemu -hdb nbd:127.0.0.1:10809
It is not accurate.
qemu connect to nbd server not "several" but exactly two times by default.
The first connection it does (it need not be a separate connection
actually, and this, I'd say, a bug in qemu) in order to guess the format
of the internal structure inside - be it raw, or qcow, or anything else.
So, if you specify the format of the device explicitly, by using
format=raw, only single connection will be made.