Re: Creating a Database on RAID 5

From: Barbara Kennedy <barbken_at_teleport.com>
Date: Thu, 19 Oct 2000 07:12:58 -0700
Message-ID: <4jDH5.6975$4u4.229909@nntp1.onemain.com>

Ed,
My empirical experience on reads and Raid 5 on over 75 different systems is that it is slow. It is easy to saturate the RAID system and that effects other users negatively. I wouldn't use raid 5 and yes it is less expensive in terms of hardware than other types of RAID, but you pay for that in performance.
Jim

"Ed Stevens" <nmmc_at_my-deja.com> wrote in message news:8smrrv$tad$1_at_nnrp1.deja.com...
> In article <8slbpb$ol2$1_at_nnrp1.deja.com>,
> EnderW <ender29_at_my-deja.com> wrote:
> > My adv. frankly donot use RAID 5, it has a write penalty....
> >
> > In article <8sl7up$l76$1_at_nnrp1.deja.com>,
> > aminocha_at_unibiz.com wrote:
> > > HI,
> > > We have a IBM Netfinity 5100 P3 /733 Mhz server running windows NT
 on
> > > it. It is a RAID Level 5 configured and has 5 HDD.
> > > I am planning to install Oracle 8.0.5 and create a database. where
 do
 i
> > > find information on how to configure the database on a RAID 5
 machine.
> > >
> > > Any help will be appreciated.
> > >
> > > Thanks
> > > Anurag
> > >
> > > Sent via Deja.com http://www.deja.com/
> > > Before you buy.
> > >
> >
> > --
> > Ender Wiggin
> >
> > Sent via Deja.com http://www.deja.com/
> > Before you buy.
> >

>

> --
> My adv. frankly donot use anything _BUT_ RAID 5, all others have a cost
> penalty . . .

>
>

> Of course, my _real_ point is that the choice of RAID configuration --
> or lack of -- depends on the situation. Yes, all else being equal
> RAID-5 has a performance hit on write operations. BUT . . . "all else"
> is never equal. RAID implemented in hardware with a good caching
> controller will improve performance over an OS implementation. More
> spindles improve the performance through increased parallelism,
> especially on read operations -- and given the application mix, this
> might acutally IMPROVE overall performance. Perhaps the application is
> simply not very write intensive when compared to the I/O capacity of the
> disk sub-system. In this case a slower write operation may very well
> not even be detectable, especially to the end user.

>

> While I don't have the benchmarks, I'd be willing to bet that the number
> of physical channels you can spread your files (and thus, your I/O)
> across has more of an impact on real throughput/response time than the
> RAID level.

>
>

> Ed Stevens
> (Opinions are not necessarily those of my employer)

>
>

> Sent via Deja.com http://www.deja.com/
> Before you buy.
Received on Thu Oct 19 2000 - 09:12:58 CDT