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Home -> Community -> Mailing Lists -> Oracle-L -> RE: 3 disks in ONE volume or 3 vols for each disk ?
here's what i have been offered...
VOL1 (1 disk) - OS VOL2 (1 disk) - OS (backup) VOL3 (1 disk) - oracle s/w, SYS, RBS, LOG01, CTL01 VOL4 (1 disk) - IDX, TMP, LOG02, CTL02
here what i propose..
remove VOL5 and make 3 separate vols mapping to a single disk then i'll have 7 physical hdisks of 9 GB each.
VOL1 - OS, LOG01, CTL01 VOL2 - OS (backup), LOG02, CTL02 VOL3 - oracle s/w VOL4 - IDX, TMP, RBS VOL5 - IDX VOL6 - DATA VOL7 - DATA
logs will be multiplexed on VOL1 and VOL2 (mirroring would be nice, but not
available) ,
i have a choice of putting redo logs on VOL3 (oracle s/w) also.. what would
be the
performance implications ?
Other way to place datafile using 7 hdisks ?
TIA Rahul
> ----------
> From: Satar
> Naghshineh[SMTP:Satar.Naghshineh_at_irvine.mellesgriot.com]
> Sent: Wednesday, September 13, 2000 12:19 AM
> To: 'George Schlossnagle'; Rahul
> Cc: K Gopalakrishnan
> Subject: RE: 3 disks in ONE volume or 3 vols for each disk ?
>
> George has an excellent point. So many sys admins fail to understand the
> implications of implementing a RAID set with only a few drives.
>
> Rahul, it seems that you have a small database since you're only using
> five drives.
> You have to make a decision here:
>
> 1. use all the 5 drives as one volume group (running RAID 5). Pro: data
> protection. Con: Possible performance degradation (based on database
> type)
>
> 2. Each disk as it's own volume group or mount point. Pro: Performance
> flexibility Con: No data protection.
>
> 3. Choose number 2 and buy another set of drives as a mirror. Con: $
>
> Regards,
> Satar
>
>
> -----Original Message-----
> From: George Schlossnagle [SMTP:george_at_omniti.com]
> Sent: Tuesday, September 12, 2000 4:31 PM
> To: K Gopalakrishnan
> Cc: Rahul; 'Oracle List I'; 'Oracle List II'
> Subject: Re: 3 disks in ONE volume or 3 vols for each disk ?
>
> Identifying hot blocks won't be a problem either. Oracle is handed
> off
> a meta-device which for all intets and purposes can be treated as a
> single regular physical device.
>
> The question of whether it's faster to use 3 individual disks or 1
> meta
> device striped across the 3 disks is dependant on the RAID level
> implemented as well as the implementing technology. Veritas (a software
> RAID product) for instance does not recommend RAID 0 striping on less 4
> physical disks - the overhead leads to no performance benefit.
>
> George
>
> K Gopalakrishnan wrote:
> >
> > Hi !
> >
> > I guess you are talking about RAID05 (or RAID 0) ?
> > In anycase you don't have control over datafile placements.
> >
> > In this case your asumption is right and if you have only
> > these three disks (and if you place your redologs on that)
> > the database will be :)
> >
> > But coming back to identifying the hot table is not
> > that difficult (you can look for dbfile_scattered/sequential
> > read stats). Tuning is almost impossible in your case.
> >
> > Regards,
> > K Gopalakrishnan
> > Bangalore, INDIA
> >
> > ----- Original Message -----
> > From: Rahul <rahul_at_ratelindo.co.id>
> > To: 'Oracle List I' <ORACLE-L_at_fatcity.com>; 'Oracle List II'
> > <oracledba_at_quickdoc.co.uk>
> > Sent: Tuesday, September 12, 2000 11:28 AM
> > Subject: 3 disks in ONE volume or 3 vols for each disk ?
> >
> > > List,
> > > i have been asked to suggest the placement of datafiles.
> > > on solaris. They have already created the volumes. For datafiles
> > > there's a big volume of 27GB, there are 3 Hdisks in that volume.
> > > I asked them to give me FIVE separate volumes to place the datafiles,
> > > but they say that using one big volume will strip the data and will be
>
> > > more faster etc...
> > > my question is... how will be identify a hot block/table on ONE big
> volume
> > ?
> > >
> > > as we dont have any control where our datafile is place , right ?
> > > and we will NOT have the option of moving the file also ..
> > >
> > > so..which one is better.. one BIG vol. or 3 small volumes mapping
> directly
> > > to
> > > each hdisks.
> > >
> > > TIA
> > >
> > > Rahul
> > >
> > >
> > > --------
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Received on Tue Sep 12 2000 - 21:54:15 CDT
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