User guide

© 2011 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information. Cisco Validated Design Page 130
8.0 Scalability Considerations and Guidelines
There are many factors to consider when you begin to scale beyond four chassis or 16 servers, which this
reference architecture has successfully tested. In this section we give guidance to scale beyond four Cisco UCS
chassis.
8.1 Cisco UCS System Configuration
As the results indicate we are seeing linear scalability in the Cisco UCS reference architecture implementation.
XenServer
No. of Chassis
No. of B250-M2
Servers Tested
No. of VMs
VMs/Core
1
1 Blade
110
9.16
2
8 Blades
880
4
16 Blades
1760
Cisco UCS supports up to 20 chassis within a single Cisco UCS domain on a Cisco UCS Fabric interconnect
6120 and up to 40 chassis on a FI 6140, extrapolating the values we got during the testing we get the following
results:
XenServer
No. of Chassis
No. of B250-M2
Servers
No. of virtual
machines
Virtual
machines/Core
8
32 Blades
3520
9.16
12
48 Blades
5280
16
64 Blades
7040
20
80 Blades
8800
To accommodate the Cisco Nexus 5500 upstream connectivity in the way we describe in the lan configuration
section, we need four Ethernet uplinks to be configured on the Cisco UCS Fabric interconnect. And based on the
number of uplinks from each chassis, we could calculate how many desktops can be hosted in a single UCS
domain. Assuming two links per chassis, scaling beyond 10 chassis would need a Cisco UCS 6140 fabric
interconnect. A 5500 building block can be built out of the RA described in this study with two links per chassis
and 12 Cisco UCS chassis comprising of four B250-M2 blades servers each.
The backend storage has to be scaled accordingly, based on the IOP considerations as described in the NetApp
scaling section.
Citrix has a modular reference architecture design that details how to scale their components as you scale the
number of desktops. Please refer to http://support.citrix.com/article/ctx124087.