cost justify 4 way vs 8 way

Is it safe to say that an 8 way will run twice as fast as a 4 way when it
comes to executing stored procs,etc.. ? Is there a way to figure out whats
the best server to obtain and cost justify it . It seems 4 way would be
ideal but how do we know whether an 8 way would really be super fast ?> Is it safe to say that an 8 way will run twice as fast as a 4 way when it
> comes to executing stored procs,etc.. ?
No. Considering that many queries cannot take advantage of two processors,
never mind 8... I doubt that doubling your CPU count could ever exactly
double the speed of the database engine. A lot more variables than that.
Chances are your best bang for the buck will be fast drives (e.g. SAN).
Most applications utilizing SQL Server database servers can run plenty fast
on 4-ways, especially since most new servers have HT (so a 4-way will
operate much like an 8-way anyway). I highly doubt, even if you do your own
testing with all your own variables, that you will be able to justify the
cost differential between a 4-way and an 8-way.
A|||I Completely agree.
Greg Jackson
PDX, Oregon|||8 way rarely runs twice as fast as a 4 way. It all depends on your work
load.
If you have plenty of IO bandwidth and you workload consists of many
concurrent queries without much contention among them, then you might get
close.
If you have a few big queries, then you should look at if the query can run
twice as fast with 8 CPU. It depends on if the query have a perfect parallel
plan or not.
If you are IO bound, then you should invest the money on better disk system.
8 way machines usually cost more than 2 times the 4 way machines.
--
Wei Xiao [MSFT]
SQL Server Storage Engine Development
http://weblogs.asp.net/weix
This posting is provided "AS IS" with no warranties, and confers no rights.
"Hassan" <fatima_ja@.hotmail.com> wrote in message
news:eG$abBVHFHA.560@.TK2MSFTNGP12.phx.gbl...
> Is it safe to say that an 8 way will run twice as fast as a 4 way when it
> comes to executing stored procs,etc.. ? Is there a way to figure out whats
> the best server to obtain and cost justify it . It seems 4 way would be
> ideal but how do we know whether an 8 way would really be super fast ?
>|||In addition to what the others have already stated if you have a true OLTP
type system you may get better throughput by adjusting your MAXDOP down. Of
coarse it depends on your workload but if you do mostly single row type
operations you may even want a MAXDOP of only 1.
--
Andrew J. Kelly SQL MVP
"Hassan" <fatima_ja@.hotmail.com> wrote in message
news:eG$abBVHFHA.560@.TK2MSFTNGP12.phx.gbl...
> Is it safe to say that an 8 way will run twice as fast as a 4 way when it
> comes to executing stored procs,etc.. ? Is there a way to figure out whats
> the best server to obtain and cost justify it . It seems 4 way would be
> ideal but how do we know whether an 8 way would really be super fast ?
>|||i went from a dual processor to a dual hyperthreaded processor and
parallel queries ran much slower on the hyperthreaded one so i had to
set maxdop at 1. microsoft really needs to improve their parallel query
execution.
"Andrew J. Kelly" wrote:
> In addition to what the others have already stated if you have a true OLTP
> type system you may get better throughput by adjusting your MAXDOP down. Of
> coarse it depends on your workload but if you do mostly single row type
> operations you may even want a MAXDOP of only 1.
> --
> Andrew J. Kelly SQL MVP
> "Hassan" <fatima_ja@.hotmail.com> wrote in message
> news:eG$abBVHFHA.560@.TK2MSFTNGP12.phx.gbl...
> > Is it safe to say that an 8 way will run twice as fast as a 4 way when it
> > comes to executing stored procs,etc.. ? Is there a way to figure out whats
> > the best server to obtain and cost justify it . It seems 4 way would be
> > ideal but how do we know whether an 8 way would really be super fast ?
> >
> >|||It's a HT issue mostly. A logical processor is not the same as a physical
one so you can't expect to get the same amount of work out of the logical
ones as the real or physical ones. Changing the MAXDOP to no more than the
number of physical processors is the first thing I recommended on HT
systems. And you should be running Win2003 to take the best advantage of HT.
--
Andrew J. Kelly SQL MVP
"ch" <ch@.dontemailme.com> wrote in message
news:422321A0.F10ED15D@.dontemailme.com...
>i went from a dual processor to a dual hyperthreaded processor and
> parallel queries ran much slower on the hyperthreaded one so i had to
> set maxdop at 1. microsoft really needs to improve their parallel query
> execution.
>
>
> "Andrew J. Kelly" wrote:
>> In addition to what the others have already stated if you have a true
>> OLTP
>> type system you may get better throughput by adjusting your MAXDOP down.
>> Of
>> coarse it depends on your workload but if you do mostly single row type
>> operations you may even want a MAXDOP of only 1.
>> --
>> Andrew J. Kelly SQL MVP
>> "Hassan" <fatima_ja@.hotmail.com> wrote in message
>> news:eG$abBVHFHA.560@.TK2MSFTNGP12.phx.gbl...
>> > Is it safe to say that an 8 way will run twice as fast as a 4 way when
>> > it
>> > comes to executing stored procs,etc.. ? Is there a way to figure out
>> > whats
>> > the best server to obtain and cost justify it . It seems 4 way would be
>> > ideal but how do we know whether an 8 way would really be super fast ?
>> >
>> >|||You are better off in upgrading to a CPU with higher/better L2/L3 Cache than
adding some more
CPUs.
Gopi
"Hassan" <fatima_ja@.hotmail.com> wrote in message
news:eG$abBVHFHA.560@.TK2MSFTNGP12.phx.gbl...
> Is it safe to say that an 8 way will run twice as fast as a 4 way when it
> comes to executing stored procs,etc.. ? Is there a way to figure out whats
> the best server to obtain and cost justify it . It seems 4 way would be
> ideal but how do we know whether an 8 way would really be super fast ?
>|||Keep in mind too that a "real" 8-way is going to cost you more than two
4-way machines, even two with HTT. So, you're going to get almost the same
amount of performance as a "real" 8-way, at less than 1/2 the cost.
Now, something you should really be looking at is a 4-way Itanium 2 machine.
Some vendors have just begun selling some and the costs are under the 2 for
1 pricing and the Itanium 2's have REAL dual parallel execution technology.
If it helps you at all, the same SQL Server licenses cost you the same, and
you can upgrade them to 64-bit without charge.
Sincerely,
Anthony Thomas
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:%23Rq$meaHFHA.2860@.TK2MSFTNGP12.phx.gbl...
It's a HT issue mostly. A logical processor is not the same as a physical
one so you can't expect to get the same amount of work out of the logical
ones as the real or physical ones. Changing the MAXDOP to no more than the
number of physical processors is the first thing I recommended on HT
systems. And you should be running Win2003 to take the best advantage of HT.
--
Andrew J. Kelly SQL MVP
"ch" <ch@.dontemailme.com> wrote in message
news:422321A0.F10ED15D@.dontemailme.com...
>i went from a dual processor to a dual hyperthreaded processor and
> parallel queries ran much slower on the hyperthreaded one so i had to
> set maxdop at 1. microsoft really needs to improve their parallel query
> execution.
>
>
> "Andrew J. Kelly" wrote:
>> In addition to what the others have already stated if you have a true
>> OLTP
>> type system you may get better throughput by adjusting your MAXDOP down.
>> Of
>> coarse it depends on your workload but if you do mostly single row type
>> operations you may even want a MAXDOP of only 1.
>> --
>> Andrew J. Kelly SQL MVP
>> "Hassan" <fatima_ja@.hotmail.com> wrote in message
>> news:eG$abBVHFHA.560@.TK2MSFTNGP12.phx.gbl...
>> > Is it safe to say that an 8 way will run twice as fast as a 4 way when
>> > it
>> > comes to executing stored procs,etc.. ? Is there a way to figure out
>> > whats
>> > the best server to obtain and cost justify it . It seems 4 way would be
>> > ideal but how do we know whether an 8 way would really be super fast ?
>> >
>> >