Citrix Systems 6 ユーザーズマニュアル

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The QoS value limits the rate of transmission from the VM. The QoS setting does not limit the amount of data
the VM can receive. If such a limit is desired, Citrix recommends limiting the rate of incoming packets higher up
in the network (for example, at the switch level).
Depending on networking stack configured in the pool, you can set the Quality of Service (QoS) value on VM
virtual interfaces (VIFs) in one of two places—either a) on the vSwitch Controller or b) in XenServer (using the
CLI or XenCenter)—as described in the following table:
Networking Stack
Configuration Methods Available
vSwitch
• vSwitch  Controller.  This  is  the  preferred  method
of setting the maximum transmission rate on a VIF
when  the  vSwitch  is  the  networking  stack.  When
using the vSwitch stack, the XenCenter QoS option
is not available.
• xe commands. It is possible to set the QoS transmit
rate  using  the  commands  in  the  example  that
follows. However, the preferred method is through
the  vSwitch  Controller  UI,  which  provides  more
finely grained control.
Linux bridge
• XenCenter.  You  can  set  the  QoS  transmit  rate
limit value in the properties dialog for the virtual
interface.
• xe commands. You can set the QoS transmit rate
using  the  CLI  using  the  commands  in  the  section
that follow.
Important:
When  the  vSwitch  is  configured  as  the  networking  stack,  it  is  possible  to  inadvertently
configure a QoS value on the vSwitch Controller and inside of the XenServer host. In this case,
XenServer limits the outgoing traffic using the lowest rate that you set.
Example of CLI command for QoS:
To  limit  a  VIF  to  a  maximum  transmit  rate  of  100  kilobytes  per  second  using  the  CLI,  use  the  vif-param-set
command:
xe vif-param-set uuid=
<vif_uuid>
 qos_algorithm_type=ratelimit
xe vif-param-set uuid=
<vif_uuid>
 qos_algorithm_params:kbps=100
Note:
If you are using the vSwitch Controller, Citrix recommends setting the transmission rate limit
in the vSwitch Controller instead of this CLI command. For directions on setting the QoS rate
limit in the vSwitch Controller, see the vSwitch Controller User Guide.
Changing networking configuration options
This section discusses how to change the networking configuration of a XenServer host. This includes:
• changing the hostname (that is, the Domain Name System (DNS) name)
• adding or removing DNS servers
• changing IP addresses
• changing which NIC is used as the primary management interface
• adding a new physical NIC to the server