Hi all,
 
I am using Centos 5.2 for both DomU and
Dom0. I used “xm block-attach” to attach a LV to a DomU and mounted
to DomU’s /mnt. 
 
I tried to run “xm block-detach vm1 /dev/sdb”,
I find that this command will hold for long time as DomU has not umount /mnt. I
have done an experiment by running “time xm block-detach vm1 /dev/sdb”.
I find that this command needs 1min 40s to timeout. Any method to shorten this
timeout? 
 
[root@localhost] time xm block-detach vm1
/dev/sdb
Error: Device /dev/sdf (vbd) could not be
disconnected. 
Usage: xm block-detach <Domain>
<DevId> [-f|--force]
 
Destroy a domain's virtual block device.
 
real    1m40.149s
user    0m0.052s
sys     0m0.044s
 
P.S. I tried xm block-detach vm1 /dev/sdb –force
, this command will result hang of DomU.
 
Regards,
Felix