On Sep 15, 1:53 pm, "Jeje" <willg...@hotmail.com> wrote:
> Virtualization become better and better everyday.
> the performance impact in a virtual machine is minimal, exists, but minimal.
> (I'm talking about CPU processing speed and IO access which are near the
> same as the host system, the overhead of the virtual env. is really small)
>
> the only big issue today, there is no support of x64 VM in virtual server.
> so running large databases in a x32 virtual machine is not so good due to
> lack of memory available in the VM.
>
> Win2008 will improve this and in fact will provide more interesting options,
> like adding CPU and memory in a VM without stopping it. So you can add cpu
> and memory, do you ETL process then remove the added cpu/memory to provide
> more power to other virtual machines.
>
> in your scenario, you want to push SSIS in a VM and the database in another.
> I think its not practical. SSIS doesn't take any resources until you run
> ETLs and communicating between the 2 VM will go through the network instead
> of using the shared memory, this will impact the database access
> performance.
> The only advantage is: you'll have 4gb a ram for SSIS and 4gb of RAM for SQL
> Server instead of 4gb of shared RAM (remember the x32 limit)
> but in this case, use the host server only and you'll have 8gb of ram all
> the time and your SQL server server will have more power when you don't run
> the ETLs (8gb memory instead of 4gb will certainly improve the SQL Server
> performance)
>
> and... again I'll repeat always the same thing: SAN is NOT A performance
> solution until you setup it correctly.
> we see a lot of customers which don't understand why their SAN is slower
> then direct attached storage for a DW usage.
> "I have paid thousand $ for my SAN and the vendor says SAN is the best
> performance and now you says to me it's too slow?"
> yes...
> in a DW you have to use high performance connectivitIES between the server
> and the SAN (note the S for the number of connections...)
> the customer setup only 1*2Gbps connection, which limit the SAN access to
> 170mbps only or the equivalent of 3 SAS drives. for a DW usage it's really a
> low value. but if you setup 2 or 3*4Gbps channels between the server and the
> SAN can provide more than 1GBPS of sequential access.
> so having a SAN can be good... but make sure you use more than 1 connection
> to make sure you'll have enough performance.
>
> "Nickg" <Ni...@discussions.microsoft.com> wrote in message
>
> news:8193F033-B260-4515-94E1-CB4DC576989E@microsoft.com...
>
>
>
> > We are creating a new environment for our BI DW. This includes servers for
> > SSIS and one for DW and disks on a SAN. Because of licensing the current
> > environment uses virtualization.
>
> > My question is, what are the drawbacks of using virtualization with MS SQL
> > server for BI DW?
>
> > Does anybody have a white paper or best practices document on the subject.- Hide quoted text -
>
> - Show quoted text -