1. How to Choose the Right Server?
We ran variety of tests on nine different servers to determine which H/W configuration is suitable for which application.Presented
here is our advice based on their results as well as other observations.
Workgroup servers have undergone a tremendous change in recent times with a lot of new technologies hitting the market. This has
made it difficult for IT decision makers to choose the right one for their organization. The demand for servers is increasing in India by
leaps and bounds, and as a result we are seeing that apart from the hardware majors, a lot of assemblers are also leaving the PC
space and jumping into the server arena. This has led to a major reduction in price of branded servers.
Today we are going through a phase where processor technologies are improving continuously and as a result we can now get a
powerful server in just a couple of Lakhs. And it is so powerful that if you had bought it ten years back, it would have been amongst
the top 50 supercomputers in the world. Such servers take up only 2 U of a server rack. This has all been made possible because of
the availability of multi-core processors. Today, if you buy a server with a dual Xeon, you get either the power of eight or four Xeon
processors, depending on whether you bought a quad core or a dual core server. Such a server not only gives you commendable
results in number crunching operations but also help you in consolidating your datacenter. For example, the new age processors
with multi-core technology provide you with Virtualization support. This means you can dedicate a single core to a given virtualized
OS (which is essentially a Server) and host 7 different server OSes on a single 2 U of a dual Quad-core server. We say 7 instead of
8, as we assume that one core would be used for the host server running the virtualization application.
You might wonder that if one is going to host 7 full-fledged servers on a single quad-core server then how
much memory can it support to cope with the load of all such virtualized servers running on top of it? Well,
rest assured, these servers are not only capable enough to take a huge amount of processing load but can
also support RAM of different capacities, starting from 8 GB to 64 GB. This is enough to host any kind of
application, including resource hungry virtualization setups.
Another happening segment related to servers is storage. This segment has essentially two concepts which
are gaining importance rapidly. The first is the penetration of Serial Attached SCSI (SAS) hard-disk. Since
long SCSI was the de facto standard for Server Direct Attached Storage (DAS). But, due to certain
limitations such as the maximum number of disks per channel and total throughout, SAS is taking its place
today. You will read more about SAS and its features, later in this article. The second concept that is gaining
importance is the use of Host Bus Adapter (HBA) cards. These are the cards that connect the Host
(computer) to storage over iSCSI, Fiber Channel, etc. Now let's discuss all of the above points in detail.
How much RAM?
When choosing a hardware configuration, remember that each application has a different requirement. For instance, if you plan to
use your server as a Web Server with a lot of static content (such as a Web portal) or as a file or networked server, then the amount
of RAM doesn't really matter much, assuming you have at least 4 GB RAM. This has become standard nowadays. We came to this
conclusion after running our set of I/O, disk and Web benchmarks, on the same server, with 4 GB and 8 GB RAM. In case of Web
requests, the performance was the same for both configurations, while in case of file server I/O, the performance improved by 10%
with higher RAM. That's hardly an increment worth spending for extra RAM.
What matters the most in these cases are disk and network speed. Once again, while testing the servers, we noticed that when you
stress a server's disk access performance over the network, then the first thing to get choked is your Gigabit Ethernet card. This
results in data transfer speeds of just below 1,000 Mbps. To rectify this, we joined two Ethernet cards while running network based
benchmarks. Such an arrangement gave us double the bandwidth. We've given a detailed report on how we ran the benchmarks in
the “how we tested' section. So here's a tip: Before thinking of upgrading your processor or RAM for I/O intensive applications, first
try teaming the free LAN cards.
Some servers came with
small from HDDs (Laptop
HDDs), to save on space and
power consumption
Which Hard Drive?
Another important parameter for I/O intensive networked servers is hard disk performance. This is also critical for database servers.
But to get optimum performance, you require a very high capacity hard disk with maximum rpm and throughput, and that too in large
numbers. You can actually get better performance out of five 10,000 rpm SATA HDDs than what you can get from two 15,000 rpm

2. SAS drives. But it depends on how much you can spend and what's more important for you. If redundancy is not important and you
have three HDDs, then you can connect all of them in RAID 0 (Stripping mode) and get some really extraordinary performance.
Now, if redundancy is extremely important, which is the case with most users, you can go for RAID 5 with more hard disks (let's say
6 instead of 3) so that you can reduce the performance degradation while writing parity information, and get performance which is
equivalent to having two disks in RAID 0.
This time we got all the
servers with hot swappable
SMPS, the max number was 3
Specs for compute intensive servers
The two key things that matter in this are of course, RAM and CPU power. Plan on going for lots of RAM and a high-speed CPU if
you're putting the server to heavy duty number crunching or memory and CPU intensive applications like virtualization. Even if you
don't have a high-speed CPU, make sure that the vendor let's you upgrade to one later. Some vendors don't offer CPU upgrades in
their server configurations. The same logic also holds valid for servers which are used for huge number crunching, for eg, for
servers that will be a node of a cluster for doing huge data processing. One very important point to note here is the architecture that
your application has been designed for. If it's designed for Intel architecture, then don't expect excellent performance on an AMD
platform, and vice versa.
We came to this conclusion after doing a very interesting exercise. While deciding benchmarks to be run on all servers for testing
processor performance we first thought of using HPL (High Performance Linpack) compiled on Intel multi-core architecture. This
benchmark was provided by Intel's Server division. When we ran this benchmark on Intel servers, it gave us 27 GFlops on Dual
Core Xeons and 53 GFlops on Quad Core Xeons. But when we ran the same test on an AMD Dual Core, we got only 4 GFlops.
This was strange as the AMD machine was, till that point, outperforming most of the other servers. We felt there was something
wrong. As a result, we approached AMD and asked them to compile and customize HPL for their dual core architecture. However,
they were not able to provide a customized HPL on time. So, we decided to use a processor testing benchmark which is more real
life and generic. Read more about how we stressed the processors of various servers in 'How we tested' section.
Hot swappable hard
disks are today the
most common
redundancy feature
of servers. All the
servers which we
received this time
had feature
More RAM slots can either be
used for redundancy by
distributing RAM in smallest
possible chunks, or it can be
used for upgradability
Service and Support
While buying a server one important aspect that should never be neglected is the kind of support and service provided by the
vendor. Different vendors have different schemes. Though most of them provide 3 years warranty, some provide services within a
specified locality, while yet others have a deeper penetration. For eg, if your server is installed in a remote location, a vendor, local
to a particular area, might not have a service center there and may take time to address your problem. However, the vendor of a
branded server, available globally, would be able to address your problem by the next working day. Some vendors tie up with local,
authorized service providers to cater to the needs of people in remote areas, where they themselves don't have any existence.
There are also vendors who provide specific services for specific needs. You need to pay for the desired service and they will make

3. sure that your problem is resolved within 4 hours from the time you called them. There are other vendors who offer you 3 year
warranty with 24x7 support. But if you plan to install your server in major cities, you might as well consider local vendors who would
have branches at least in the major cities and would be more cost effective.
Manageability
These days servers ship with embedded sensors in chassis and motherboard, which can help you extract information using server
agents and send them to a centralized remote console. Monitoring the server's health and well-being remotely is a key concern for
all. Some of the servers we received had Server Management port that enables you to monitor your server over the network. The
servers also included an Intel Deployment kit that has a graphical interface and helps you configure your server easily. Also, the
Intel System Management software allows you to monitor disk space usage and has the option to alert the administrator when
updates for firmware and BIOS are required. Some vendors also provide their own customized Server Management CD through
which you can monitor the performance and health of the server, get reports on regular basis and install the desired OS.
Another important component of manageability is Out of Band management also known as LOM (lights out management) which lets
you remotely manage the server irrespective of the status of server. Using this you can only configure the settings before the OS
boots, i.e. RAID, BIOS level configuration. Two popular ways of Out of Band management include Console redirection and BMC
(Baseboard Management Controller) management card. The console redirection is done through the serial port with mostly a
modem attached to it, you can send keyboard input and receive text output, no GUI output is supported. BMC lets you interact with
distributed management cards using IPMI (Intelligent Platform Management Interface). BMC now comes integrated with most of the
boards else you can also add a separate BMC card.
Reliability and Fault Tolerance
Servers are critical for any establishment and hence their reliability is crucial. Any kind of hardware failure not only causes data loss
and server downtime but also affects the business economy. To ensure that you avoid any kind of hardware issues, it's always
preferable to have redundancy features in the server, which take care of data protection and will continue to run the server, even if
one component fails. RAID is always considered to be a vital solution for servers. If a server is storing high-value user data it is
preferable that they use RAID 5 configuration, which can only be achieved with minimum of 3 hard disks.
While RAID provides protection against single disk failure, you will need your hard disk to be hot swappable to make sure that you
can replace the faulty drive without bringing your server down. So Hot Swappable HDD enables you to replace the faulty drives with
a new one while your systems are still running. This also enables you to avoid any unnecessary downtime.
Fans are vital for any server; they help to keep the server cool, so as to avoid any performance bottleneck. Every server is equipped
with certain number of fans which are required to keep the server cool and performing, but if one fan goes for a toss then their might
be a possibility that your server performance will decrease as it generates more and more heat.
So a hot swappable fan will enable you to replace the faulty fan even while the server is running. Another key requirement is to have
a hot plug and redundant power supply which make the server fault tolerant against the failure of an SMPS or even it can take care
of power failure in case of single phase failure or power cable failure if configured properly.
There are a few other very critical aspects of reliability that must also be kept in mind. These include a server's resistance to
extreme temperatures, humidity, and vibrations. If you're buying servers for locations across the country, then you must ensure that
the server can withstand these environmental conditions in those areas.
We had contacted ERTL Lab, which is a govt-owned test lab for environmental factors. However, we were not able to pursue it
much due to shortage of time. Nevertheless, it's always good to ask the vendor for some reports on how well can it withstand
environmental factors.
Expandability
With the growing need of users and organization, one of the vital decisions while buying a server
would be the expandability. A server should have enough options for expandability should the
need arise in the future. As user needs are growing, so is the data. So storage capacity is one of
the most vital expandability options. What is the maximum number of disks the server allows you
to add?
We have seen that a maximum of 8 drive slots are available in a server, while some offer 6 drive
slots and 4 is standard across others. An SAS (Serial Attached SCSI) can accommodate up to
1600 plus devices in one channel compared to SCSI which can accommodate only 32. SAS uses
serial communication instead of parallel method and hence is capable of providing higher speed
data transfer. So SAS is preferred over SCSI nowadays. As far as SATA is concerned it offers
lesser expansion in terms of number of disks. An external SCSI connector enables you to connect
external SCSI devices like tape drives without the need to open the server cabinet for connecting it.
You also need to consider how many DIMM slots are supported by the server as they help you to add additional RAM, so if your
server supports 16 GB of RAM but there are only 4 DIMM slots available that means you need to plug a 4 GB RAM in each of the
slot, which might be an expensive affair. So more the number of DIMM slots, better it is. Also, PCI-X (64-bit) slots help you to add
additional fiber channels or RAID cards, which you might include as the need arises. Hence you are also required to consider the
number of free PCI-X slots available. RAM upgrade capability of a server can go up to a maximum of 64 GB, while some offer 32
Hot swappable Fans are
something which we saw for
the first time. Two out of nine
servers we received had this
feature

4. GB, 16 GB upgradeability was common across most of them. Any server providing less than 16 GB of RAM upgrade option is not
worth the deal, as more and more applications are becoming memory hungry and sooner than later you will require higher RAM
support.
The maximum
number of RAM
slots we this time
was 16 and came
with an assembled
server
Now with Quad Core already available in the market, processor upgradeability is an option that must not be neglected. Almost all
vendors offer processor upgradeability, there are some who don't offer it as a field operation, even though processor can be
upgraded on the same socket.
HBAs (Host Bus Adapters) are one of the most sought options in servers. Though not many vendors provide it as a default option,
still it can be additionally added and it helps you to add host system to other network and storage devices. We have mainly looked
into fiber optic HBA which acts as gateway to external SAN, though there are other types as well like ATA, SAS/SATA, eSATA etc.