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When it comes to RAID there are three benefits:
High reliability Low price High performance
Pick the two you want. I am not being facetious about this. There is a tradeoff. RAID 5 will give you low price and high reliability at the expense of performance. RAID 1+0 will give you high reliability and high performance.
There are three potential problems with RAID 5 on NT:
regards
Jerry Gitomer
coakleyj_at_hotmail.com wrote in message <7kd6sg$ds7$1_at_nnrp1.deja.com>...
>A couple of fundamental questions regarding RAID 5 configurations for an
>Oracle OLTP application, involving 60% query, 40% writes approximately
(NT
>4)-1. In general, which is the better configuration (and why) - Six 9GB
>10K RPM disks or Three 18GB 10K RPM disks - both configured as RAID 5. (I
>presume the more disks the better to reduce disk I/O?). Is there an upper
>limit to the number of disks that can be configured as one RAID set
>(before management overhead becomes too large)?2. In terms of the amount
>of disk space "used-up" on the RAID parity - how does this differ in the
>above configurations? How is this calculated? - It seems to be a function
>of the number and size of the disks in the RAID set. Is there a formula?3.
>What are the implications of the "stripe width" when configuring the system
>- What's "normal" ? How does this interact with the O/S block size (if at
>all), and how do these settings interact with the Oracle block size
>setting? Which drives the Oracle block size - the stripe width or O/S block
>size?4. Previous questions and answers on this SIG have suggested that
>RAID 5 decreases write performance whilst improving reads. The reason given
>(I think) was that the write involved 2 writes really - one for the data
>and one for the parity. Does the same logic not apply to reads - i.e. with
>RAID 5 we need to perform 2 reads instead of one ? Hence reads are slower
as
>well??Can the system be configured to optimize reads over writes or vice
>versa?5. Finally, a licensing issue regarding NT4- Assuming we have 50
>concurrent Oracle users on an NT4 server. Given that the users are
operating
>client-server and only need "ping" capability to the NT server (i.e. the
>end-users are not set up as users on the NT server, nor do they have access
>to the disk drives), do we need to licence 50 users of NT or not? If not,
>how many?RegardsCoakleyj
>
>
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>Share what you know. Learn what you don't.
Received on Fri Jun 18 1999 - 14:06:34 CDT