[Pw_forum] SATA vs SAS

Thu Aug 7 14:48:32 CEST 2014

I completely agree with Axel, expecially speaking about a middle-range
machine (as mine, for example, a linux home-assembled server with a careful
look at the costs).

Carlo

2014-08-07 14:18 GMT+02:00 Axel Kohlmeyer <akohlmey at gmail.com>:

> On Thu, Aug 7, 2014 at 6:56 AM, siddheshwar chopra <sidhusai at gmail.com>
> wrote:
> > Dear Sir,
> > Oh I am sorry... I think I didn't mention correctly.. I said "write
> times"..
> > It is actually "number of write times". Ofcourse these are very fast..But
> > their life is shorter than the normal HDDs...
> > Yes budget is what is the final verdict.. :-)
>
> not only that. but also, how much time you save, i.e. how much value
> you attribute to your own time.
> if an SSD will wear out and become unusable, you can easily replace it
> at the fraction of the cost of the entire machine, and then - provided
> an SSD scratch does significantly improve your calculation run times -
> you have a faster machine all the time.
>
> please also note that SSD performance varies a lot and also the amount
> of guaranteed writes.
>
> axel.
>
>
> >
> > Regards,
> >
> >
> > On Thu, Aug 7, 2014 at 4:18 PM, Carlo Nervi <carlo.nervi at unito.it>
> wrote:
> >>
> >> I'm not an expert, and maybe my infos are old, but I think you are
> wrong.
> >> Certain SSD have degraded performances, however the best SSD have much
> >> faster access I/O time than than the best HDD. at least for medium
> >> workstation. Cost for Gb is of course much higher for SSD, but in this
> case
> >> I would go only for a working directory to be placed on a SSD partition
> (128
> >> Gb could be enough). I do not know how is the situation for high-end
> >> enterprise solutions or supercomputers, but in this case i suspect that
> the
> >> special HDDs are not connected via simple SATA or SAS, and in these
> cases
> >> very probably they are much faster (again at much hgher prices) due
> several
> >> optimized performances (independent memory cache, for example).
> >>
> >> In other words, it depend how much is your budget...
> >> Cheers,
> >>  Carlo
> >>
> >>
> >>
> >> 2014-08-07 11:42 GMT+02:00 siddheshwar chopra <sidhusai at gmail.com>:
> >>>
> >>> Dear Sir,
> >>> I just want to participate in this good discussion. I read somewhere
> that
> >>> Solid State Hard Disk has LESSER write times than a normal HDD. Yes
> >>> undoubtedly it is the fastest we have in the market with low power
> >>> consumption and zero mechanical failure risk, but at the cost of
> shorter
> >>> lives and more money.
> >>> Any comments welcome..
> >>>
> >>> Regards,
> >>>
> >>>
> >>> On Thu, Aug 7, 2014 at 2:16 PM, Carlo Nervi <carlo.nervi at unito.it>
> wrote:
> >>>>
> >>>> My two cents: even though there are differences between SAS and SATA,
> >>>> they are not so huge.
> >>>> From this point of view I guess that a fast Solid State Hard Disk
> would
> >>>> make the difference on the I/O.
> >>>>
> >>>>
> >>>>
> >>>> 2014-08-07 10:06 GMT+02:00 Paolo Giannozzi <paolo.giannozzi at uniud.it
> >:
> >>>>
> >>>>> On Wed, 2014-08-06 at 18:15 -0400, Eduardo Menendez wrote:
> >>>>>
> >>>>> > Is it critical to use SAS disks (compared to SATA) for good
> >>>>> > performance of Quantum ESPRESSO?
> >>>>>
> >>>>> I guess it depends upon the amount of I/O you plan to do
> >>>>>
> >>>>> Paolo
> >>>>>
> >>>>> --
> >>>>> Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
> >>>>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> >>>>> Phone +39-0432-558216, fax +39-0432-558222
> >>>>>
> >>>>> _______________________________________________
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> >>>>> http://pwscf.org/mailman/listinfo/pw_forum
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> --
> >>>>
> >>>> ------------------------------------------------------------
> >>>> Prof. Carlo Nervi carlo.nervi at unito.it  Tel:+39 0116707507/8
> >>>> Fax: +39 0116707855      -      Dipartimento di Chimica, via
> >>>> P. Giuria 7, 10125 Torino, Italy.    http://lem.ch.unito.it/
> >>>>
> >>>>
> >>>> _______________________________________________
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> >>>
> >>>
> >>>
> >>>
> >>> --
> >>> Dr. Siddheshwar chopra,
> >>> M.Sc., Ph.D (Physics)
> >>> Assistant Professor (Physics),
> >>> Amity University, Noida, India.
> >>>
> >>>
> >>> _______________________________________________
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> >>> http://pwscf.org/mailman/listinfo/pw_forum
> >>
> >>
> >>
> >>
> >> --
> >>
> >> ------------------------------------------------------------
> >> Prof. Carlo Nervi carlo.nervi at unito.it  Tel:+39 0116707507/8
> >> Fax: +39 0116707855      -      Dipartimento di Chimica, via
> >> P. Giuria 7, 10125 Torino, Italy.    http://lem.ch.unito.it/
> >>
> >>
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> >
> >
> >
> >
> > --
> > Dr. Siddheshwar chopra,
> > M.Sc., Ph.D (Physics)
> > Assistant Professor (Physics),
> > Amity University, Noida, India.
> >
> >
> > _______________________________________________
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> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
>
>
> --
> Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
> College of Science & Technology, Temple University, Philadelphia PA, USA
> International Centre for Theoretical Physics, Trieste. Italy.
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-- 

------------------------------------------------------------
Prof. Carlo Nervi carlo.nervi at unito.it  Tel:+39 0116707507/8
Fax: +39 0116707855      -      Dipartimento di Chimica, via
P. Giuria 7, 10125 Torino, Italy.    http://lem.ch.unito.it/
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