Re: Use mixed sizes drives in the same Raid string

[Charles Wilt <charles.wilt@xxxxxxxxx>]

Another benefit, the validation that your backups are good!

Better to find that out now when you can put the original disks back
in, than to find out later!

Charles

On Thu, Apr 15, 2010 at 9:15 AM,  <rob@xxxxxxxxx> wrote:
> It's not just the saving of a few euros.  It's also
> - Reduction in power consumption.  That side car is going to suck energy
> and require additional power feed(s).
> - Increase in speed.  The 70GB drives are 15K speed versus 10K speed.  If
> you're bad at math that's a 50% increase in speed.  Extremely significant!
>  This speed will outweigh the additional disk arms you will be getting.
> Been there, done that.
> - Affect on cooling.  You add a sidecar, you add BTU's.
>
> You are running an i.  Therefore you can have faith in your backups
> (providing you follow the steps).  Hundreds of us have done
> unloads/reloads.
>
>
> Rob Berendt
> --
> Group Dekko Services, LLC
> Dept 01.073
> Dock 108
> 6928N 400E
> Kendallville, IN 46755
> http://www.dekko.com
>
>
>
>
>
> From:   Marco Facchinetti <marco.facchinetti@xxxxxxxxx>
> To:     Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
> Date:   04/15/2010 09:00 AM
> Subject:        Re: Use mixed sizes drives in the same Raid string
> Sent by:        midrange-l-bounces@xxxxxxxxxxxx
>
>
>
> Thanks very much to all, at the end it's probably we follow the path of an
> expansion unit (around 1.500 euro) plus some " dirt cheap" disks  4326
> (35gb
> 15k). Total cost of swapping 8 disk, double save, system reload and the
> risks involved in such operation are not worth the saving of few hundreds
> euros.
>
> By the way mixing in the same raid set disks with diffrent capacity is
> still
> not allowed even with more modern controllers?
>
> Thanks again
>
> MarcoF
>
> 2010/4/14 <rob@xxxxxxxxx>
>
> > I have to agree with the others.  70GB drives are dirt cheap.  We just
> > disposed of a huge quantity of them and what we got for them wasn't
> much.
> > Granted, the horse trader has to make a little profit.  With all the
> labor
> > involved, replace them all with 70's.
> > Besides, aren't the 70's 15K drive speed and the 35's only 10K drive
> > speed?
> http://www-947.ibm.com/systems/support/i/planning/upgrade/futurehdwr.html
> > <snip>
> > Although IBM plans to support all existing i5/OS 15k rpm disk drives and
> > the i5/OS 10k rpm 35.16GB disk drive on POWER6 based System i models, it
> > is generally recommended for better performance that customers use 15k
> rpm
> > disk drives where possible. The 10k rpm 35.16GB disk drive is
> represented
> > by feature code #4319/#7501 or CCIN #6719.
> > </snip>
> >
> >
> > Rob Berendt
> > --
> > Group Dekko Services, LLC
> > Dept 01.073
> > Dock 108
> > 6928N 400E
> > Kendallville, IN 46755
> > http://www.dekko.com
> >
> >
> >
> >
> >
> > From:   Marco Facchinetti <marco.facchinetti@xxxxxxxxx>
> > To:     midrange-l@xxxxxxxxxxxx
> > Date:   04/14/2010 06:57 AM
> > Subject:        Use mixed sizes drives in the same Raid string
> > Sent by:        midrange-l-bounces@xxxxxxxxxxxx
> >
> >
> >
> > I'va a customer using 87% of the installed disks (246 Gb) so I have to
> > find
> > how to increase the total amount of disk space without an expansion unit
> > (no
> > available slots for new disks).
> >
> > The machine is  a 9405-520, the controller a 573D-001 with 8 disks
> (4326),
> > Raid5 is active. Total available space is  246 Gb.
> >
> > My 1st question: may I mix in the same raid set drives with diffrent
> > capacity (eg. 36 and 70 gb)?
> >
> > If posssible should I expect any perfomance problems?
> >
> > If not possible should I split the raid in two strings (eg. 4x4326 and
> > 4x4327) or I must change all the drives?
> >
> > Any suggestion is much appreciated.
> >
> > TIA
> >
> > MarcoF
> > --
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