April 13, 2008 at 10:16 pm
Hi,
Not sure if this should be in here or in some other forum, but will give this a nudge; we are going to be sourcing a new box for our OLAP operations; specifically for SSAS to sit on.
Not having a lot of experience with SSAS, I am a little unsure as to what specifics I should be using in order to spec' this new box.
There is always the old adage of 'as much as you can afford', however I would like to be able to put forward a solid proposal for a box with some sound reasoning as to why x, y and z is necessary.
Is anyone able to offer any insight or pointers?
Thanks in advance
Troy
April 14, 2008 at 7:56 am
Most of the major hardware vendors have sizing tools (Dell here, HP's ). For the devils advocate-side of using the sizing tools, see this article from sql server magazine.
Generally with AS memory is the key, although if you've got really (really) large datasets, then disk will also be an issue. As with most DB systems, *fast* disk is always good too 🙂 Unless you're working iwth quite small datastes, I'mnot sure why you'd go with 32bit (assumes your data is large and growing frequently).
HTH,
Steve.
April 15, 2008 at 3:11 pm
Thanks for the response and the links! I had a look at them, plugged in the numbers and was amazed at how different the results were!
Hp rekoned we need a single cpu dual core with 24GB of RAM (using the DataMart option)
where as Dell rekoned we need a quad core cpu with 8GB of RAM (using the DSS option)
I do wonder if I am over complicating the process and should just spec something up as per which way the wind is blowing 😀
What we have at the moment is 150GB d/b size
210million rows in our main fact table with an average width of 330bytes
Concurrent users are about 20-30 at any one time
Our OLAP environment is only a couple of years old and is expected to grow somewhat; in the calculations I factored in a 50% growth rate over the next 3 years.
I was thinking something along the lines of a dualcore (maybe quad but not fussed), with some nice fast disk and with something like 8-10GB of RAM.
I know the old adage of as much RAM and as fast disk as one can afford; but really, I would have thought 24GB (as per recommendation from HP) was a little over the top *shrug*
Anyhow keen to hear peoples thoughts.
Cheers
Troy
April 15, 2008 at 3:34 pm
I know it's not a prescription per se for sizing (and it's a little dated now, has nothing newer has come through?) but could give you some food for thought - have you looked at the Project Real documents re: the Unisys servers they used?
You also mention that you have an OLAP environment already, is it AS2k5 and if so, what is your current SSAS DB size(s)?
Steve.
April 15, 2008 at 4:23 pm
I havn't had a chance to read any of their white papers on previous implementations; but will have a dredge.
Our current OLAP environment is on the same server as our normal RDBMS environment; both are SQL2005. Our normal DB stuff is taking a hit while processing the OLAP and servicing the requests(or is that vise versa ?? *shrug*); hence the requirement to move to a seperate box.
Just checked the size of our OLAP db's and the largest (of which there are 2) is only 4GB :hehe: with a number of other smaller ones.
April 16, 2008 at 10:22 pm
no one else has any comments on which factors to consider in order to drive some specifications for an OLAP server?
April 21, 2008 at 7:39 am
You're in the right ball park. As always, how much you buy depends on user expectations, design, size, etc, etc, etc.
Some comments:
- I'm surprised your MSAS database is so small, given the size of your data source. I'm going to assume you've built aggregations, etc.
- If you had to choose between the two options, I'd go for the 24 Gig Memory (and dual core). The more that get's loaded into memory, the better. MSAS relies on the disk cache to bring relevent cube parts into memory, so it's best not to starve it if you can avoiud it.
- The concurrent users will push you into more CPUs. How heavy their usage is will govern how important that is, and that depends on the application.
Given your sizes, I'd suggest a profile of about 12-16 gig, 4 to 8 cores (you pick how to achieve this). Make sure you you can tweak these numbers upward a little if you need it.
And oh, yes, go 64 bit.
April 30, 2008 at 12:53 am
beauty thanks for the response!
(and sorry for the late reply on my behalf)
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