Transcript Network Bottlenecks - The ICT Help Center

Computer and
Network
Bottlenecks
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
Introduction
A bottleneck (the slowest component in your computer
network) causes work to get jammed up. The first step in
improving network performance is to identify the
bottleneck.
The Hardware Inside your Servers
Your servers should be powerful computers capable of
handling all the work your network will throw at them.
Don't cut corners by using a bottom-of-the-line computer
that you bought at a discount computer store.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
The following are the four most important components
of your server hardware:
Processor: Your server should have a powerful processor.
As a general rule, any processor that is available in an
$800 computer from a low-cost general appliance store is
not a processor that you want to see in your file server. In
other words, avoid processors that are designed for
consumer-grade home computers.
Memory: You can't have too much memory. Memory is
cheap, so don't skimp. Don't even think about running a
server with less than 2GB of RAM.
Author: Rodger Burgess
27th October 2008 © Copyright reserved
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Network Bottlenecks
Disk: Don't mess around with IDE hard drives. To be
respectable, you should have nothing but SATA drives.
Network card: Cheap $14.95 network cards are fine for
home networks, but don't use one in a file server that
supports 50 users and expect to be happy with the
server's performance. Remember that the server computer
uses the network a lot more than any of the clients. So
equip your servers with good network cards.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
The Server's Configuration Options
All network operating systems have options that you can
configure. Some of these options can make the difference
between a pokey network and a zippy network.
Unfortunately, no hard-and-fast rules exist for setting
these options. Otherwise, you wouldn't have options.
The following are some of the more important tuning
options available for most servers:
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
Virtual memory options: Virtual memory refers to disk
paging files that the server uses when it doesn't have
enough real memory to do its work. Few servers ever
have enough real memory, so virtual memory is always
an important server feature. You can specify the size and
location of the virtual memory paging files. For best
performance, you should provide at least 1.5 times the
amount of real memory.
For example, if you have 1GB of real memory, allocate at
least 1.5GB of virtual memory. If necessary, you can
increase this size later.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
Disk striping: Use the disk defragmenter to optimize the
data storage on your server's disks. If the server has more
than one hard drive, you can increase performance by
creating striped volumes, which allow disk I/O operations
to run concurrently on each of the drives in the stripe set.
Network protocols: Make sure that your network
protocols are configured correctly and remove any
protocols that aren't necessary.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
Free disk space on the server: Servers like to have plenty
of breathing room on their disks. If the amount of free
disk space on your server drops suddenly low, the server
chokes up and slows to a crawl. Make sure that your
server has plenty of space — a few gigabytes of unused
disk space provides a healthy buffer.
Servers that do too much
One common source of network performance problems is
servers that are overloaded with too many duties. Just
because modern network operating systems come
equipped with dozens of different types of services
doesn't mean that you should enable and use them all on
a single server.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
If a single server is bogged down because of too much
work, add a second server to relieve the first server of
some of its chores. Remember the old saying: "Many
hands make light work.“
What Services does Microsoft Server 2003 have?
There are many services available in Server 2003. It is
important to remember when invoking a service on a
Server, there should be no other service currently
activated . The following screen shows what services are
available.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
For example, if your network needs more disk space, consider
adding a second file server rather than adding another drive to the
server that already has four drives that are nearly full. Or, better yet,
purchase a file server appliance that is dedicated just to the task of
serving files.
As a side benefit, your network will be easier to administer and more
reliable if you place separate functions on separate servers. For
example, if you have a single server that doubles as a file server and
a mail server, you'll lose both services if you have to take the server
down to perform an upgrade or repair a failed component. However,
if you have separate file and mail server computers, only one of the
services will be interrupted if you have to take down one of the
servers.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
The network infrastructure
The infrastructure consists of the cables and any
switches, hubs, routers, and other components that sit
between your clients and your servers. The following
network infrastructure items can slow down your
network:
Hubs: Because switches are so inexpensive now, you can
affordably solve a lot of performance problems by
replacing old, outdated hubs with switches. Using
switches instead of hubs reduces the overall load on your
network.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
Segment sizes: Keep the number of computers and other
devices on each network segment to a reasonable
number. About 20 devices is usually the right number.
(Note that if you replace your hubs with switches, you
instantly cut the size of each segment because each port
on a switch constitutes a separate segment.)
The network's speed: If you have an older network, you'll
probably discover that many — if not all — of your users
are still working at 10Mbps. Upgrading to 100Mbps will
speed up the network dramatically.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
The backbone speed: If your network uses a backbone to
connect segments, consider upgrading the backbone to
1Gbps.
The hardest part about improving the performance of a
network is determining what the bottlenecks are. With
sophisticated test equipment and years of experience,
network gurus can make pretty good educated guesses.
Without the equipment and experience, you can still
make pretty good uneducated guesses.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
Network Bottlenecks
Malfunctioning components
Sometimes a malfunctioning network card or other
component slows down the network. For example, a
switch may malfunction intermittently, occasionally
letting packets through but dropping enough of them to
slow down the network. After you've identified the
faulty component, replacing it will restore the network to
its original speed.
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Author: Rodger Burgess
27th October 2008 © Copyright reserved
The End
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Author: Rodger Burgess
27th October 2008 © Copyright reserved