Indexes on separate Filegroups

Two questions. Let's suppose I have two file groups, Primary and Datagroup.
The Primary group is mirrored and has my system tables and transaction log
(Drive letter "D"). My tables and indexes are in the Datagroup on a separate
RAID 5 disk configuration (Drive letter "E"). Let us suppose I have available
a third RAID 5 disk configuration (Drive letter "F").
1. I just wanted to verify a thought: If all my tables have clustered indexes,
and since clustered indexes reside on the data pages themselves, then it
would NOT make sense to put my clustered indexes on a separate file or disk
from my data file. True or False? My guess is that the answer is true. Please
verify.
2. In the case of non-clustered indexes (where all the corresponding tables
have clustered indexes), there could possibly be a performance gain by
placing the non-clustered indexes on a separate file (say, Drive letter "F")
from my data. True or False? My guess is that the answer is true. Please
verify.
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"cbrichards via droptable.com" <u3288@.uwe> wrote in message
news:5e60b49711dd2@.uwe...
> Two questions. Let's suppose I have two file groups, Primary and
> Datagroup.
> The Primary group is mirrored and has my system tables and transaction log
> (Drive letter "D"). My tables and indexes are in the Datagroup on a
> separate
> RAID 5 disk configuration (Drive letter "E"). Let us suppose I have
> available
> a third RAID 5 disk configuration (Drive letter "F").
> 1. I just wanted to verify a thought: If all my tables have clustered
> indexes,
> and since clustered indexes reside on the data pages themselves, then it
> would NOT make sense to put my clustered indexes on a separate file or
> disk
> from my data file. True or False? My guess is that the answer is true.
> Please
> verify.
>
True. That would just move the tables to the other filegroup.

> 2. In the case of non-clustered indexes (where all the corresponding
> tables
> have clustered indexes), there could possibly be a performance gain by
> placing the non-clustered indexes on a separate file (say, Drive letter
> "F")
> from my data. True or False? My guess is that the answer is true. Please
> verify.
False. Seperating tables and indexes rarely helps, and is essentially an
obsolete micro-optimization of the physical database design. The large
memory size of modern servers makes physical IO on your non-clustered
indexes rare and unpredictable enough that you shouldn't dedicate a physical
IO channel to your indexes. A better idea would be to spread all your
objects across both disks by adding additional files to your data filegroup,
or monitor your physical IO and move objects to the other disk to roughly
balance the traffic.
David