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in this issue:
your career as a network/system administrator
Most of the time we are swamped in daily issues
like fixing problems and etc. But have you considered the bigger
picture of how to advance your career? For example, in five years from now, will you
be still in the same post doing the work as
today? Do you want to become a senior network/system
administrator, DBA, help desk manager, information security
officer, IT manager, or even IT director or CIO?
You may think these are impossible, but there are
actual things that you can do to increase your chances. You first need
to see what the gap between your current status and the desired
position is. Usually there are several types of gaps:
- Gap in the breadth of skill. For example, you
may be good at Windows server but knows nothing about Exchange or
Linux. The easy solution is to write down a simple plan, like, "I will
attend a course on Linux in 2010 Q2" and then stick to it.
- Gap in the depth of skill. For
example, you aren't strong enough in Windows server. This gap
is much toucher to close. Typically training cannot turn an average
cook into a good cook. A way to close this gap is to keep practicing
(keep cooking and adjusting for better results) and learn from experts
(observe how great cooks do it). A great way to practice is to attempt
to answer questions on technical forums and verify the solutions
offered by others. For example, commit to attempting one question every
- Gap in aptitude. This is the hard part. If
you're used to blaming the tools, your boss, your colleagues or
Microsoft instead of solving the problems, then it is difficult to
advance to a senior post.
Below are the major skills that I think
should be important for each post:
|Senior network administrator
||Routing, switching, wireless, VoIP, VPN,
firewall, IDS/IPS. Ability to ensure availability, security,
performance in the architecture.
|Senior system administrator
Exchange, Sharepoint, Apache, virtualization, storage. Ability
to ensure availability, security, performance in the architecture.
||Oracle, SQL server, MySQL.
|Information security officer
||CISSP, CISA, ISO 27001, computer forensics,
risk management, project management.
|Help desk manager
||ITIL, communication (NLP), quality management, human resource management.
||ITIL, communication (NLP), project
management, quality management, , human resource management, vendor management, outsourcing management, risk management.
||Ditto, plus the ability to support the CEO to transform the enterprise with IT strategies.
careful with RAID5 and SATA disks
you're using or going to buy SATA disks to be used by a server, you
should be careful in deciding to use RAID5. This is because a
disk will encounter an error reading a sector once it has read
certain number of bits. What's the problem with RAID5 then? If
of the disk in a 3-disk RAID5 array fails, once you plugin a replacement
hard disk, the two disks must be read from start to end to reconstruct
the array. If one of the disk has reached that limit and encounters a
reading error, the array will fail to reconstruct.
How likely is it? Many SATA disk has an
bit error rate of 1014. It means that the disk
will be unable to read a sector if it has read 1014
bits. If the disk is say 1TB in size (1012)
which is 8*1012
bits. If you read the whole disk from start to end once, there is a
chance of 8*1012/1014=8% that it will be unable to read a sector. During the
reconstruction phase, the probably of having exactly one disk
failing is 2*8%*92%=14.72%. The actual probably for failure
higher because the probability of both disks failing was not
addition, the larger the disk is, or, the more disks you have
the array, the more likely the reconstruction will fail. For example,
if you have six disks and each disk is 2TB, the probability for exactly
one of the remaining disks failing during the process
is 5*16%*(84%)4=39.8%. Again, the
multiple disks failing was not included. It means that once a disk is replaced, RAID5 may be degenerated into no RAID at all.
So, what should you to prevent this problem? There
are several solutions that you may consider:
- Use RAID6 instead of RAID5. RAID6 uses two
disks to store the parity.
So, even if a disk can't read a sector during reconstruction,
it can still
go ahead. The probability for exactly two of the remaining
disks failing during the process is (5*4/2)*(16%)2*(84%)3=15.2%.
- Buy SATA disks that have a lower bit error
rate. There are some offerring 1015
which is ten times better. The probability for exactly one of
remaining disks failing during the process is 5*1.6%*(98.4%)4=7.37%.
- You could buy SCSI disks that achieve
a bit error rate of 1016. Of course, they are
also much more expensive.
at 1/5 of the cost of Cisco's?
We all know that Cisco routers are very expensive.
For example, it costs several thousand MOP just to upgrade the
IOS to support IP security. But why not use Linux on top of a standard
x86 server as a router? To do that, we need to ensure the performance,
support and ease of management. Now there is a company that aims to
put a trimmed down version of Linux on a standard IBM x86 server to
create a high end router, at 1/5 of the cost of a similar Cisco router. In terms of permformance, it is rivaling
a Cisco 7200 router. In terms of support, it provides all
kind of support services up to 7x24 and consulting services. Regarding
management, it has a command line interface that looks very similar to
IOS, so you will feel right at home. For junior administrators, it has
a web-based interface.
Vyatta has won the best
of open source networking software award in 2009. As it is
open source, you can always try it out yourself to see if it fits your
courses for network administrators
or experiences to share? Contact me at 88980601 or email@example.com. We
have 3 more
newsletter, Software developer newsletter and E-flow newsletter.