Virtualization and I/O bottleneck blades are suitable for virtualization

Lucero, a technology director at Vmpower, a consultancy at the beginning of 2007, said: "The number of blade network cards is limited and does not apply to virtualization." He said that in the configuration of the server virtualization application, Vmpower recommended to install more than one network card, "never less than 6 network cards (ports), up to 14." "There are similar restrictions on the Fibre Channel (FC) and memory capacity on the blades compared to the rack-top servers.

Similarly, there are users in the country who are questioning the suitability of the blade server for hosting virtualization applications. According to a server manufacturer Product technology manager, often received requests from users, hope to be able to from the blade server on the ship down. The Product manager pointed out that with the promotion of virtualization applications, a common physical server would be divided into multiple virtualized servers, while processor efficiency was increased, but more load would put greater pressure on server I/O. He pointed out that because of the special design of blades, the limited bandwidth of blades and backplane (or midplane), this congenital deficiency would aggravate the I/O bottleneck, so the blade server was not suitable for hosting virtualization applications.

Virtualization and I/O bottlenecks

Speaking of virtualization business applications, Hewlett-Packard Industry standard Server Product Manager Liu Hongchen pointed out that, whether it is a blade server, or a rack server, the impact of virtualization applications is mainly reflected in: processor performance, memory capacity, I/O, disk read and write speed and green energy saving five aspects. In particular, he stressed that virtualization is a complex process in which users are required to perform overall assessment, planning and management in advance.

VMware Technology Director Zhang Zhenlen pointed out that virtualization applications must be integrated planning, so as to avoid the proliferation of virtual machines. He said that at present, many manufacturers have provided a specialized tool to help users to make a reasonable assessment of existing applications, at the same time, manufacturers also provide professional advisory services. Novell Senior Engineer Yang Yinhong points out that not all user applications can be virtualized, while users are not advised to centralize the same type of application to a single physical server. Yang Yinhong stressed that users should be based on the actual needs, reasonable choice of virtualization scheme.

Liu Hongchen points out that in the five factors that affect virtualized business applications, the blade server is no different from the rack server in terms of the processor, so it doesn't matter whether it's good or bad. In the memory capacity, disk read and write speed these indicators, blade server is not behind the rack-type server, users can analyze and compare. As for the green energy conservation, because the blade server uses the sharing power, the heat dissipation as well as the network unique shooting way, therefore has the obvious superiority compared with the rack-type server. He says the current contradictions focus on I/O bottlenecks.

It is understood that for the I/O bottlenecks caused by virtualization, the usual way for a rack-like server is to extend the I/O with PCI slots. Earlier, Vmpower technical director Lucero is using this approach. Compared with the rack-type server, Blade server's high integration design, limited space makes its I/O extension Limited, the need to use a dedicated network card and a variety of HBAs, the so-called dedicated is relative, the current blade server also provides a variety of brand options. For example, HP Blade server, there are Cisco, Brocade, foundry and HP and other brands to choose from.

In terms of extensibility, the HP Blade server is equipped with two expandable slots, plus a standard NIC on the motherboard that actually has 3 slots. According to the introduction, HP's one network card can support 2 or 4 network ports, a network port is equivalent to a network card, calculated down, equivalent to full with 12 network cards. Liu Hongchen says there is no case for such a level of exposure in the current case. When allowed, in addition to the NIC, the Blade module can also connect a variety of HBA cards, to occupy the expansion slot. In this respect, the blade server also provides a mezzanine expansion card that occupies the adjacent slots of the blade module and provides an extension to the blade module. It is understood that up to now, no user has proposed the purchase of mezzanine expansion card needs. In fact, the use of mezzanine expansion cards is often used. Some users may know that some brands of blade servers are standard and do not support hard drive hot plug, its support for hard disk hot plug, and memory expansion is done through a similar mezzanine approach.

It is understood that in the current domestic users of the application, it is really necessary to use some special card, such as encryption cards, serial expansion cards, and so on, some of them are based on PCI protocol. For these special cards, the blade does not provide support. Therefore, for the user whether to adopt blade server, really need to judge according to the actual situation.

In addition, the need to clearly describe the so-called blade module and backplane bandwidth. According to Liu Hongchen, HP's backplane design does not have any electrical indicators, belongs to a pure connector design, but even so there is the problem of bandwidth. At present, HP Blade server backplane bandwidth of 5Tbps, users can calculate their own, there is no so-called bottlenecks.