REMOVING SKELETONS
FROM YOUR SERVER
CLOSET
Dr. Natheer Khasawneh
Rafat A. Dasan
This chapter will cover…
• Offers guidance on how to upgrade an existing Data Center that is
lacking in space or infrastructure, has been poorly maintained, or can
no longer meet your company's hosting needs because of changes in
the types of equipment that are to be installed.
• Addresses the special challenges of retrofitting a less-than-perfect
server environment with the least impact to devices that are already
on line.
• Provides tips on how to relocate a Data Center with the least possible
disruption and downtime.
Topics to be covered …
Lack of Space
Chaos
Infrastructure
Shortcomings
Paradigm
Shifts
Acquisitions
Large-Scale
Server Moves
Lack of Space
• One of the most common reasons for upgrading a Data
Center is simply that it has run out of physical space to
host new equipment. This could be because the server
environment was undersized during its initial design or,
hopefully, because a company has prospered and
requires more servers and networking devices to handle
its expanding business functions.
• This can be achieved by
• Space Saving Measures
• New Construction
Space Saving Measures
• Rerack servers— Review how existing Data Center equipment has been
installed.
• Are there gaps between servers? Move devices closer together so that they occupy
less cabinet space.
• Are devices sitting on the raised floor that can be rack-mounted instead? Install
them into cabinets to free up floor space.
• Can large monitors in cabinets be replaced with smaller ones? While a standard
computer monitor occupies 10U or more when placed on a cabinet shelf, there are
rack-mountable models that open and shut like a laptop computer. They occupy only
1U in a cabinet, and a user slides out an extendable tray to open them to viewing
size. It's also possible to link multiple devices to a single monitor, using a switch box
to change displays, thereby freeing up even more cabinet space.
• Reorient floor- standing devices—Rack-mountable servers aren't the only
items that need to be arranged in order to conserve space. Make sure
that floor-standing machines are positioned to occupy as few cabinet
locations in the Data Center as possible. For example, if a storage unit
has a door on one side that needs to swing open to insert or remove
media, place the unit at the end of a server row. This enables the aisle to
provide the clearance space for the door rather than sacrificing a usable
cabinet location.
Space Saving Measures (Cont.)
• Upgrade to smaller devices— Today's servers, networking devices, and storage units are
almost universally smaller and faster than yesterday's. Consider upgrading to newer devices
as a strategy to recoup floor space. In some instances it can even be cheaper to buy a new
model of server than to continue paying service contracts to support older ones. This is
especially true when older systems are replaced by a smaller number of new machines.
While some approaches to upgrading server performance can be difficult to sell to upper
management due to their costs, a solution such as this that saves money, provides better
performance, and delays the need to expand a space-constrained Data Center is an obvious
winner.
• As you pack equipment tighter in the Data Center, watch out for hot spots. The most dramatic
consolidations might require additional electrical and cooling infrastructure. While additional
infrastructure doesn't come cheap, it is still much less expensive than paying to expand the
entire room.
• Remove old equipment— Are decommissioned devices sitting on the Data Center floor or
occupying space in server cabinets? System administrators are often diligent about installing
new equipment but not as attentive about removing outdated gear. That is understandable,
because there is no project or application being held up if a leftover server isn't immediately
removed. Allowing old items to accumulate wastes valuable floor and cabinet space and
adds unnecessary weight to the Data Center floor, however, so work with Data Center users
to have equipment removed in a timely manner. When new servers or networking devices
arrive for installation, check with the owner to see if they are replacing devices that can now
be removed.
• Reorient major infrastructure to share buffer space— Depending upon the layout of your
existing Data Center, you may be able to reclaim some floor space by relocating air handlers
and power distribution units so they begin to share buffer areas. This approach is presented
in Chapter 4, "Laying Out the Data Center," for new
New Construction
• Even after consolidating equipment as much as possible, you
might find you are simply outgrowing the existing Data Center
and that building additional server environment space is your
only option.
• If the Data Center was designed with expansion in mind and a
dedicated growth path already exists, your course of action is
easy. Simply design the expansion space the same way that
you would a completely new Data Center.
• Assuming that the existing server environment has successfully
met your company's needs to date—how it is laid out, the type
and amount of infrastructure components available at each
server cabinet location—then duplicate its design in the new
space, making what minor adjustments are precipitated by the
footprint of the expansion space.
New Construction (Cont.)
• knock down the wall making one contiguous server
environment vs. keep wall up and create two separate but
adjacent rooms.
• The advantages of two spaces come from their
segmentation. If their respective infrastructure systems
are kept distinct, it is possible that a problem in one
room—say an air handler fails or a fire breaks out—might
not spread to the other.
• The disadvantage of two rooms is that the dividing wall
between them occupies significant space. If you knock
down the wall of the existing Data Center and expand into
the growth area, you don't have to lose usable floor space
to a dividing wall and associated aisles.
New Construction (Cont.)
• If you decide to make a contiguous Data Center, take
precautions to protect servers in the original room during
construction. Hang thick layers of material between the
old and new spaces to prevent dust, dirt, or other
contaminants from entering the old space. Also limit
ingress into that area by contractors. Finally, when testing
the Data Center's entire electrical system, you must
decide whether it is acceptable to incur downtime to
servers and networking devices in the original space or
whether you want to skip portions of the power tests that
shut down all power to the room.
Chaos
• Before embarking upon a major construction project to
add infrastructure or expand an overworked server
environment, see if any of the following can remediate the
problems and make the space more usable:
• Use the right length patch cords for the job
• Add wire management
• Make sure that people are correctly using infrastructure
• Install power strips with known electrical ratings: Do you know how
much equipment you can install into your server cabinets before
you overload their power strips? If not, you are either underutilizing
server cabinet space or risking downtime every time you plug in
new equipment.
• Redeploy floor tiles —If cooling is a problem and your Data Center
has a raised floor, check that floor tiles are deployed to best
advantage.
Chaos – Cont.
Infrastructure Shortcomings
• Another reason to retrofit a Data Center is because the room
lacks a particular infrastructure. Power, data cabling, cooling,
fire suppression, and structural support all have the potential to
be lacking as a server environment fills with equipment.
• Power
• If a Data Center can't provide enough power to servers and networking
devices, it is generally because it has no more circuits available, not
that its power distribution units are unable to provide enough raw
electricity.
• Second, although a Data Center's electrical system should be
designed as if every server cabinet is drawing the maximum possible
load, few cabinets actually do. Drawing maximum power from a server
cabinet power strip poses the risk of tripping its circuit breaker, so most
installations leave a margin for safety. This small amount of unused
electrical capacity adds up to a lot of amps over the span of a large
Data Center.
Infrastructure Shortcomings – Cont.
• Connectivity : lack of connectivity is one of the easier issues to address. It
can be remediated in one of two ways.
• One option is added structured cabling. As long as the installer is careful to work
around existing servers and their connections, the upgrade can usually be
completed without any downtime. This cabling needs to terminate somewhere in the
Data Center, however, either at a network substation or a main networking row.
• A second option, particularly when the need is for copper connections, is to install
either of two networking devices—a console server or console switch—at the
cabinet where more ports are needed. These networking devices can send multiple
streams of information over one signal, a process known as multiplexing
• Cooling : There are many techniques for improving cooling in a server
environment. Here are five:
• Relocate air handler temperature sensors
• Install ducted returns
• Distribute servers
• Install self- cooling cabinets
• Install additional air handlers
Infrastructure Shortcomings – Cont.
• Fire Suppression : It is possible, that your company might want to
upgrade the fire suppression system that was originally installed in your
Data Center. It could be that the room was designed and built with wet
pipe sprinklers, and you want to replace them with preaction dry pipe to
reduce the risk of water spilling onto servers due to a leak or pipe break.
Maybe the Data Center was designed without a gaseous fire suppression
system, and at a later date you decide to add it for greater fire protection.
• Structural Support : Yet another possible shortcoming is your Data
Center being unable to support enough weight to accommodate incoming
servers. Before you reach the maximum weight-bearing ability for your
Data Center, take the following steps to lighten the room's load:
• Shed unnecessary cabinet weight —If you have a choice among what types of
server cabinets are deployed in your Data Center, use those that weigh the least.
Remove doors from cabinets that don't need to lock to secure servers. Take off the
side panels, too, especially if you aren't using them to channel server exhaust into a
hot aisle.
• Enforce a maximum weight for fully-loaded cabinets
• Place heaviest items in rows with structural columns
• Distribute servers
Paradigm Shifts
• It is also possible that your Data Center has ample physical room and infrastructure
available and yet still begins having problems hosting incoming equipment. This occurs
when servers, networking devices, or other machines arrive that the server
environment wasn't designed to accommodate.
• Maybe server manufacturers alter their designs, making machines that need more
physical space or electrical power. Perhaps your company decides to pursue a different
business goal, requiring equipment that your Data Center never had to host in years
past.
• Here are several tips to follow when making significant infrastructure changes to your
existing Data Center:
• Upgrade the room in phases, say a couple of server rows at a time, rather than trying to overhaul
it all at once.
• When retrofitting the Data Center dictates physically moving equipment, take advantage of
devices that have dual power supplies.
• If work in the Data Center might produce debris or airborne particles, shut down the fire
suppression system to avoid setting it off accidentally.
• If new servers are installed in the Data Center while it is undergoing a retrofit, place them
according to how the room is going to be designed ultimately
Acquisitions
• Finally, your business might acquire or merge with another
company, and in the process end up with one or more
additional server environments that are functional but
inconsistent with your established Data Centers. The challenge
here is deciding how much to change in the interest of
standardization.
• If your company plans to keep the facility, definitely perform
any non-intrusive alterations that can make the server
environment more consistent with your other Data Centers.
Apply your standard labeling scheme to the room's structured
cabling and electrical conduits, for example, and install
telephones and monitoring lights as you would in a new Data
Center. If the server environment is disorganized, use the
suggestions listed earlier in this chapter to clean up how patch
cords and power cables are routed.
Large-Scale Server Moves
• Involves the daunting task of moving hundreds of servers (
have anew DC). Here are several techniques for making such
a large-scale equipment relocation proceed smoothly and
quickly:
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•
•
•
•
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Have a plan
Hire professionals
Prioritize equipment
Run a special backup
Label items with destination information
Pre-cable patch cords —It can be time-consuming to redo thousands
of data connections, from scratch, following a move. If you leave patch
cords dangling from servers and secure them carefully during the
move process, you can likely just plug them back in at their destination
location.
• Have spares at the ready
• Leverage dual power supplies
Summary
• One common problem of infrastructure shortcoming is running out of space to
host equipment. To mitigate this, rerack servers close together, share monitors
between devices, position floor-standing machines to occupy the least space,
upgrade to smaller servers, and quickly remove decommissioned servers from the
Data Center floor.
• Another cause for retrofitting a Data Center is the room having become
disorganized with its infrastructure components hopelessly tangled. To mitigate
this, swap out overly long cables, remove cords that aren't attached to functioning
equipment, add wire management where needed, replace power strips that have
unknown electrical ratings, and rearrange floor tiles to improve airflow.
• Yet another reason to upgrade a server environment is the room having run short
on certain infrastructure. Power shortcomings, lack of connectivity and , Cooling
problems
• Last, you might need to retrofit a server environment that is obtained through the
acquisition of another company. Upgrade the room to match your Data Center
standards as much as possible. It is much easier to manage multiple server
environments if they all contain the same level of infrastructure.