Re: Use mixed sizes drives in the same Raid string

[John Jones <chianime@xxxxxxxxx>]

It may not matter to your client, but if they are contemplating moving to a
Power7 system in the not-too-distant future, the Power7 550 does not support
drives smaller than 70GB (internally or in a rack/side car).  I don't see
any reason to believe the 720, or whatever the 520's replacement will be
called, will be different.

On Thu, Apr 15, 2010 at 8:51 AM, Marco Facchinetti <
marco.facchinetti@xxxxxxxxx> wrote:

> Inline2010/4/15 <rob@xxxxxxxxx>
>
> > 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).
>
> This is a point that supposed to be important (at least to my consience)
> but
> the customer main business is selling energy so I don't think they are so
> sensitive about this matter
>
>
> > - 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.
>
> If I'm not wrong 4326 are 15k, see:
>
>
> http://www-03.ibm.com/systems/resources/systems_power_hardware_reports_io_specs.pdf
>
> - Affect on cooling.  You add a sidecar, you add BTU's.
> >
>
> See the first point...
>
>
> > 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.
> This is the sad part: most of the 520 of my customers mount tape 6384
> (30/60
> gb) so there are two negative point:
>
> - This unit is not reliable as used to be in other formats (I have some
> customers with a very high rate of device failure)
> - The system save requieres 3 tapes so the customer has to pay samebody for
> it.
>
> At the end the balance is so "balanced" that (I think) the customer will
> choose the expansion unit.
>
> Let's see
>
> Thanks again
>
> MarcoF
>
> > Rob Berendt
> > --
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