I just started a couple days ago at this client.
They're using Hitachi technology in the QA and prod
environment with 181G disk. I asked the SA twice and
he confirmed the 181 G disk.
I'll ask more details to the SA as soon as I know him
better.
- "Deshpande, Kirti" <kirti.deshpande_at_verizon.com>
a écrit : > John,
> I agree with the 18GB drives implementation and
> pushing for more 'parity
> groups'. That's what we did. Now, HDS was back to
> sell more disk and backup
> soultions to us. I am not sure what we have agreed
> to purchase. A cache of
> 10GB for the 400GB database is nothing. I bet you
> will have tables larger
> than the cache size. A single FTS on these tables
> will flush the whole
> cache... We have 16GB cache (I think I remember that
> right, and is the max
> for 7700E), and that is not enough for several
> servers that the cabinet
> supports.
>
> - Kirti
>
> -----Original Message-----
> Sent: Wednesday, April 10, 2002 7:08 PM
> To: Multiple recipients of list ORACLE-L
>
>
>
> Thanks for all the replies. We are determined
> to lay out the data as
> well as we can across the disks we are about to
> purchase - with the goal of
> striping across array groups and smaller, faster
> drives. The real
> argument for us is 18GB vs. 73GB disk drives and how
> we can stripe. The
> Hitachi is configured into groups of 4 physical
> disks called "parity
> groups" and you can choose RAID 5 or RAID 1+0 for
> that 4 disk set. If
> you have 73GB drives in a 4-disk RAID 5
> configuration you get roughly 219GB
> of usable space in each parity group (this is what
> we are being told is the
> best option for us). This means our heavily
> concurrently accessed 400GB
> production database goes on 2 parity groups (2 sets
> of 4 disks). To
> me, this sounds like a nightmare waiting to happen
> and we are trying to
> stop it. The 18GB drives are less capacity but we
> can get ourselves
> spread over more parity groups for better
> concurrency. We do have about
> 10GB of cache but it is being shared across the
> enterprise with various
> other applications. We as a DBA group are
> really trying to sell the
> 18GB RAID 1+0 drive solution especially after
> reading the groups'
> experiences - unfortunately we are fighting a lot of
> marketing hype.
>
> If anyone has additional experiences or feedback
> with Hitachi or EMC they
> would like to share or comments (agree/disagree)
> with my thoughts, I'd love
> to hear them. I'm open for learning!
>
> Thanks,
>
> John Dailey
> Oracle DBA
> ING Americas - Application Services
> Atlanta, GA
>
>
>
>
>
>
> "Don
>
> Granaman" To:
> Multiple recipients of list
> ORACLE-L <ORACLE-L_at_fatcity.com>
> <granaman_at_cox cc:
>
> .net> Subject:
> Re: disk subsystem
> performance question
> Sent by:
>
> root_at_fatcity.
>
> com
>
>
>
>
>
> 04/10/2002
>
> 01:08 PM
>
> Please
>
> respond to
>
> ORACLE-L
>
>
>
>
>
>
>
>
>
> Short answer - NO! Nobody's disk subsystem is so
> fast that no intelligence
> is required in the layout. This is common vendor
> blather and one of the
> most popular myths. I have been hearing it for at
> least six years - and it
> still isn't true. Layout still makes a huge
> difference. RAID levels still
> make a huge difference. Cache won't solve all your
> problems (it does help
> though). I've redone the disk layout on some of the
> biggest, fastest
> fully-loaded with cache EMC Syms available that had
> some "don't worry about
> it" layout and seen database throughput go up by as
> much as 8x.
>
> See Gaja's whitepaper on RAID at
> http://www.quest.com/whitepapers/Raid1.pdf
> .
>
> Don Granaman
> [certifiable oraSaurus]
>
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L"
> <ORACLE-L_at_fatcity.com>
> Sent: Wednesday, April 10, 2002 10:38 AM
>
>
> > Hi all,
> >
> > We are running both a Hitachi 7700E and a 9960
> disk subsystem here and we
> > are getting ready to move our production DBs from
> the old(7700E) to the
> > new(9960) Hitachi. We have had trouble in the
> past on the 7700E due
> to
> > disk contention and layout, i.e. we weren't
> striped across the array
> groups
> > very well.... this caused pretty poor I/O
> performance. This has
> been
> > a learning experience for the DBAs and the SAs
> here for the logical vs.
> > physical aspects of our disks. Anyway, to
> make a long story short,
> we
> > are ordering disk for the move to the 9960 and we
> have 2 choices in disk
> > sizes - 18GB and 73GB, and 2 choices in RAID - 1+0
> and 5. I would
> like
> > to get the smaller, faster 18GB drives in a RAID
> 1+0 configuration and
> > stripe our data across the array groups as wide as
> possible. However,
> I
> > am running into objections from the Hitachi people
> that their system is
> > "soooo fast we need not worry about such minor
> details". I'm having a
> > hard time believing that given our I/O problems on
> the 7700E.
> Performance
> > is given a high priority here.
> >
> > What I would like to know is others' experience
> with disk subsystems -
> > specifically Hitachi but EMC and others as
> well.... have you been able
> to
> > "throw the disk in and forget it" or have you had
> success in getting to
> the
> > dirty details? Have you tested or noticed an
> improvement with
> smaller,
> > faster drives in a disk subsystem like the Hitachi
> or have you traveled
> > that path and found no noticeable improvement?
> I'm looking for
> either
>
=== message truncated ===
Stéphane Paquette
DBA Oracle, consultant entrepôt de données
Oracle DBA, datawarehouse consultant
stephane_paquette_at_yahoo.com
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Received on Thu Apr 11 2002 - 07:28:21 CDT
