Re: Question about Sun disk space configuration for large Oracle database

"Richard Piasecki" <ogo_at_mailexcite.com> wrote in message news:<3b7084a6$1$249$45beb828_at_newscene.com>...
> Greetings.
>
> I am currently developing the physical disk space layout for a large Oracle
> database (over 2 terabytes of disks), and I wish to solicit some opinions as
> to how to make this work. My configuration calls for each Oracle tablespace
> to be placed on separate RAID 0+1 arrays. Each RAID array would be
> controlled
> by its own RAID controller. There are 13 such arrays and the largest of
> these
> arrays needs to be at least 550 Gigs. The system administrator with whom I
> am working on this project has reviewed Sun hardware specs and has come to
> the conclusion that 13 RAID controllers is not do-able. Instead, he
> recommends using fewer RAID controllers and allowing each one to control
> multiple arrays. I am primarily concerned with reducing I/O contention for
> the Oracle tablespace files and wonder if a single RAID controller can
> handle
> multiple requests for different arrays in parallel. There is another problem
> in that, according to his analysis, each RAID 0+1 array can accomodate, at
> most, 8 disks. Assuming 36 gig disks, this would mean that the largest size
> of a single RAID 0+1 array would be 144 gigs (4x36), significantly less than
> my 550 gig target. Below, you will see my proposed physical layout for each
> partition and its use. My questions for the Sun/Oracle experts are as
> follows...
>
> 1) If I allow a single RAID controller to handle multiple arrays, how can
> I minimize I/O contention to those arrays. Can a single RAID controller
> handle multiple requests to different arrays in parallel?
> 2) How do I set up a partition of 550 gigabytes? Can a single array be
> composed of 32 disks (assuming RAID 0+1 with 36 gig disks)?
> 3) Specifically for the Oracle DBAs, would you recommend any changes to
> the proposed configuration to improve performance?
> 4) If you were in my shoes, how would you do it? What specific Sun hardware
> should be used?
>
> My company's upper management does not have the time right now (due to a
> very tight product development schedule) to bring in Sun reps to get
> answers to these questions, so I greatly appreciate whatever assistance
> the USENET community can provide.
>
>
> PROPOSED CONFIGURATION
> ----------------------
>
> Dir Size Usage Recommendation
> ---- ----- ------------------------- -----------------
> / 50 GB All system software Four(4) 36 GB dsks RAID 0+1
> /u01 2 GB First Online Redo Logs Part of root (/)
> /u02 2 GB System tablespace Two(2) 36 GB dsks RAID 0+1
> /u03 6 GB Temporary tablespace Two(2) 36 GB dsks RAID 0+1
> /u04 100 GB Archived redo & exports Six(6) 36 GB dsks RAID 0+1
> /u05 2 GB Second Online Redo Logs Two(2) 36 GB dsks RAID 0+1
> /u06 8 GB Rollback for Data 1 Two(2) 36 GB dsks RAID 0+1
> /u07 8 GB Rollback segments Two(2) 36 GB dsks RAID 0+1
> /u08 80 GB Indexes for Data 1 Six(6) 36 GB dsks RAID 0+1
> /u09 550 GB Data 1 Thirty-two(32) 36 GB dsks RAID
> 0+1
> /u10 12 GB Indexes for Data 2 Two(2) 36 GB dsks RAID 0+1
> /u11 60 GB Data 2 Four(4) 36 GB dsks RAID 0+1
> /u12 4 GB Indexes for Data 3 Two(2) 36 GB dsks RAID 0+1
> /u13 8 GB Data 3 Two(2) 36 GB dsks RAID 0+1

Just few remarks.
1) You have not enough space for indexes. For Data 1 just 1/7 of tables, for Data 2 only one fifth. i recommend as minimum 1/3 or you can easily overflow your index space.
2) I do not think that good position for first redo logs is part of /. Maybe better is to put REDOs somewhere in ORA inst, which should be placed separately from OS, so instead of

/ 50 GB All system software Four(4) 36 GB dsks RAID 0+1
is better this

/      30 GB    All system software         Two(2) 36 GB dsks RAID 1
/ora   30 GB    Oracle software             Two(2) 36 GB dsks RAID 1

3) Which external disk array you want to use ? 4) If you need a lot of perfomance, then is better to have one controller for each array. You can have more external storages for one server so there should be no problem you mentioned above. ... of course if your budget is not too tight.
BTW: I not fully understand the limit of 8 disks to one array. You talk about physical array (one external box), or logical (one part of external box) ? I do not know SUN products in this area.

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Dusan Bolek, Ing.
Oracle team leader