Filegroup question

I was reading an article about the use of filegroups. I had alsways thought
that multiple files/ filegroups were pretty much pointless unless they were
on they're own raid array? However this article seems to disagree with that
theory and say that multiple files on the same disk array could improve
performance? Whats your take on this? And if its true, why not just split
your whole db into multiple files on the same disk array? Heres a snippet of
the article:
/*
If your database is very large and very busy, multiple files can be used to
increase performance. Here is one example of how you might use multiple
files. Let's say you have a single table with 10 million rows that is heavily
queried. If the table is in a single file, such as a single database file,
then SQL Server would only use one thread to perform a read of the rows in
the table. But if the table were divided into three physical files (all part
of the same filegroup), then SQL Server would use three threads (one per
physical file) to read the table, which potentially could be faster. In
addition, if each file were on its own separate physical disk or disk array,
the performance gain would even be greater.
*?SQL will in different circusmstances be more aggresive in IO based on the
number of files. Is that good or bad if all the files are on the same array?
Well, like any performance question, the answer is it depends. <g>
You might get better performance this way if the 'single array' is a super
duper fast array on an EMC SAN. You might get worse performance if you're
on a low end arrary.
However, there are other cases where you might want multiiple files, on the
same array, irregardless of IO performance.
Take a look at this article...
http://www.windowsitpro.com/Article/ArticleID/40615/40615.html
--
Brian Moran
Principal Mentor
Solid Quality Learning
SQL Server MVP
http://www.solidqualitylearning.com
"ChrisR" <ChrisR@.discussions.microsoft.com> wrote in message
news:B17EA0E2-638C-45CD-B160-C9E304549ADB@.microsoft.com...
> I was reading an article about the use of filegroups. I had alsways
thought
> that multiple files/ filegroups were pretty much pointless unless they
were
> on they're own raid array? However this article seems to disagree with
that
> theory and say that multiple files on the same disk array could improve
> performance? Whats your take on this? And if its true, why not just split
> your whole db into multiple files on the same disk array? Heres a snippet
of
> the article:
> /*
> If your database is very large and very busy, multiple files can be used
to
> increase performance. Here is one example of how you might use multiple
> files. Let's say you have a single table with 10 million rows that is
heavily
> queried. If the table is in a single file, such as a single database file,
> then SQL Server would only use one thread to perform a read of the rows in
> the table. But if the table were divided into three physical files (all
part
> of the same filegroup), then SQL Server would use three threads (one per
> physical file) to read the table, which potentially could be faster. In
> addition, if each file were on its own separate physical disk or disk
array,
> the performance gain would even be greater.
> *?