Re: Oracle on a VA7400 from HP

Sorry Vartan, not that easy, most of what you said I already know, the array indeed is a black box, but on the OS there are as far as I understood two things you have to consider, first of all (we got two channels from the OS to the array). To implement load balancing across the two channels you need at least two LUNS which you combine in one Volume group. Each LUN has got a different primary channel.
Second you can set a stripe size on your logical volume. Seeing our OS LVM block size is 8Kb and also our Oracle block size is 8Kb, we are talking about setting this stripe size to 8Kb or a multiple of that. Question is if there is anyone out there that got experience with setting this stripe size, some other sources suggested 64Kb.

Thanks in advance,
John  

Vartan Narinian <vsn_at_pobox.com> schreef in artikel <a69t6u087uo974sujjpcbktub8udriepch_at_4ax.com>...
> "John van Eck" <JvanEck_at_ssc.dordrecht.nl> writes:
> >
> >The HP consultant however did not know much about Oracle, so with
setting
> >the logical volume stripe size (lvcreate) he could not give any advice
on
> >how the set the stripe size.
> >We got OS and database block sizes of 8Kb, so the stripe size should be
8Kb
> >or a multiple of 8Kb. So far so good. But because you have no control of
>
> What do you mean by stripe size? Are you creating multiple LUNs and then
> combining them into a single volume group and striping across? Why? The
> whole idea of the array is that you request a chunk of disk space and the
> array gives it to you. You cannot control placement of data on the array
> -- the array may switch between RAID levels and even migrate data between
> disks as disks are added, LUNs are created or disks are removed or
> hotspared. Only create as many LUNs as you would have created volume
> groups (for logical separation of data, not for performance).
>
> You have to forget the traditional practise of DBAs controlling placement
> of data by optimizing disks, logical volumes, stripe sizes etc. In any
> case, the array has about half a Gig of cache, so unless your data flow
is
> really really huge, you'll be reading/writing to memory most of the time.
> Things have changed, long live the new flesh.
>
> --
> Vartan
>
Received on Tue Feb 19 2002 - 02:06:50 CST