Re: -- SQL 2005 memory (x64) --

Just want to add that cost is often one of the key factors in considering
RAID5 vs. RAID10. With the same number of drives, RAID5 gives you more usable
space, and thus cheaper in terms of dollars/GB.

Also, in addition the often-cited general performance comparison between
RAID5 and RAID10 (and some other RAID config's), one should keep in mind the
requirements of the app in question. If RAID5 meets the performance
requirements of the app you are deploying, it may be a perfect choice even if
you may get better performance from a RAID10 config.

Linchi

"Ekrem Önsoy" wrote:

First of all, I'm not a RAID expert. However, I read about RAIDs a lot so I
just shared my idea with you.

However, it would be very useful to test this kind of configuration before
implementing it. Test RAID5 and RAID10 for your environment if you have
time.

You said that your I\O rate is mixed read and write. For this kind of mixed
needs RAID10 is recommended.

Generally tests say that RAID1' s write performance is much more good over
RAID5, so use RAID1 for your log files. RAID5's read performance is much
better than RAID1's so locate your data files on a RAID5. However, if write
rate is high in your environment, than a RAID10 would be more appropriate
for your data files.

After deciding which RAID configuration(s) is the best for your particular
environment, then locate your database log files and data files on different
physical disks according to those RAID choices.

These opinions are from the tests people perform in their environments. We
can not be sure these results would work for everybody perfectly. So, the
best is test test and test it again.

I'll give you some links below, see yourself. Also, read the comments in
those pages.
http://weblogs.sqlteam.com/billg/archive/2007/06/18/RAID-10-vs.-RAID-5-Performance.aspx
http://www.astro.ufl.edu/~ken/perf_tests.html
http://sqlblog.com/blogs/linchi_shea/archive/2007/02/07/is-raid-5-really-that-bad.aspx

--
Ekrem nsoy
http://www.ekremonsoy.net , http://ekremonsoy.blogspot.com
MCBDA, MCTS: SQL Server 2005, MCITP:DBA, MCSD.Net, MCSE, MCT



"Edmundo J. Davila" <edavila@xxxxxxxxxx> wrote in message
news:91FF0342-72B9-42F8-8BBC-E5FE203E485C@xxxxxxxxxxxxxxxx
Ekrem,

I read Mr. Kagel's article about RAIDs. I'm not complety sure that RAID10
is the best option if I want performance. In backing up and don't have any
doubt that RAID10 is better than RAID5 (because of the redundancy). I have
a database server with high reading and writing operations. I'm not sure
if RAID10 will make the writing process slower than RAID5.

Edmundo J. Davila
Ekrem nsoy" <ekrem@xxxxxxxxxxxx> escribi en el mensaje de noticias
news:7473FF0A-8F12-48C5-8E7C-2E6C4DD65054@xxxxxxxxxxxxxxxx
Hello Edmundo!

Answers are in lines.

--
Ekrem nsoy
http://www.ekremonsoy.net , http://ekremonsoy.blogspot.com
MCBDA, MCTS: SQL Server 2005, MCITP:DBA, MCSD.Net, MCSE, MCT



"Edmundo J. Davila" <edavila@xxxxxxxxxx> wrote in message
news:066B9EFE-EDC3-4AF5-AF01-509F3263EF73@xxxxxxxxxxxxxxxx
Ekrem,

Thank you for your answer.

I have the following doubts:

1. If 64 bits architecture doesn't need AWE, Why is the option
available in the SQL Server 64 bits?

Honestly, I don't really know why that checkbox is exist in x64 version
of SQL Server. I'll ask you to check out the following document from BOL
to learn more about usage of AWE option in SQL Server 2005 and why it's
not necessary to use it in x64 systems.

http://msdn2.microsoft.com/en-us/library/ms175581.aspx


2. I'm supposing SQL Server is using a maximum of 2GB of RAM, because I
can't increase the maximum server memory in the SQL Server (the top is
2147483647)? Because of that I can't set (at least from the interface)
the maximum memory of SQL Server to 4GB.

2147483647 is MB, not KB or BYTE. This is a default and max value.


3. Why do you think is better RAID10 than RAID5. As far as I know (I'm
not an expert on RAIDs) RAID10 would be slower because of the
redundancy.

Take a look at the following article by S. Kagel:
http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt

Your answer has been very useful. I'll appreciate your comments
regarding to my doubts.

Edmundo J. Davila



.

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