[AccessD] Needs analysis

Thanks Drew.

When it comes to raid, my issue is money.  Raid 10 requires 4x the drives for x storage.  Raid6 
requires x+2 drives for x storage.  If you take an example... I have a 16 port coprocessor (TWELVE 
HUNDRED DOLLARS!).  4X storage means the most storage I can get on that is 4 gigs using 1 gig drives.

X+2 means I could get 14 gigs theoretically.  In fact I have two 4 gig arrays (12 drives) plus a 2 
drive raid 0 plus a 2 drive raid 1.

Yea, if I were made of money I would do things differently, but this is a one man shop here, not 
Microsoft (who can afford to throw money at it).

John W. Colby
www.ColbyConsulting.com


Drew Wutka wrote:
> Memory and processor can also go more and faster, but to throw my two
> cents in, drop the RAID 6.
> 
> http://en.wikipedia.org/wiki/Standard_RAID_levels
> 
> http://en.wikipedia.org/wiki/Nested_RAID_levels
> 
> RAID 0 gives you the best performance of any RAID.  However, it has NO
> redundancy, so if you lost one drive, you lose all your data.  RAID 5 is
> probably the worst for performance, and RAID 6 is a little better (well,
> RAID 1 in some scenarios is worse..it has NO write advantage, and in
> older implementations, RAID 1 doesn't let both drives read at the same
> time, but most new RAID controllers do this, so RAID 1 , in a two drive
> system would read at the same speed as a RAID 0 with 2 drives.)
> 
> I personally recommend RAID 10 (or RAID 1+0).  That is NOT RAID 0 +1
> (there is a difference, described in the second link.  One is a mirrored
> stripe, the other is a striped mirror.  RAID 1 +0 gives you the absolute
> best performance along with redundancy.  And as you can see in the
> second link, that's what is recommended for database systems, in fact,
> it's what MS recommends for exchange servers.
> 
> Drew
> 
> 
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of jwcolby
> Sent: Saturday, June 19, 2010 10:57 AM
> To: Access Developers discussion and problem solving
> Subject: [AccessD] Needs analysis
> 
> I am about to upgrade my SQL server.  Currently I run a quad core with
> 16 gigs ram, using data on 
> raid6 arrays with a dedicated raid co-processor.  I have an opportunity
> to build a server that 
> better meets my needs but I need to discover what those needs are.
> 
> As I have posted previously I process fairly substantial lists where
> (for example) I will join a 
> table with 20 million names to a table with 65 million names on a sha
> hash field and select by a 
> half dozen field criteria.  Stuff like that.  My databases are,
> generally speaking, read-only.  This 
> is not transaction stuff, but rather "data mining" kind of stuff.
> 
> These queries can take a long time to run, tens of minutes or more.
> What I would like to find out 
> is what is the bottleneck.  If I increased my memory to 32 gigs would
> that be enough?  Would 64 gigs 
> be better or not be any better than 32 gigs?  How much memory do these
> queries want?  If I increased 
> my cores to 8 or 16 would that be enough?  How many threads would these
> queries use?  If I moved 
> some of the database onto SSDs would that help more than additional
> memory?  How much time / 
> resource is spent loading the data off of disks.
> 
> I have absolutely no idea how to discover this kind of information.  I
> am going to have X dollars to 
> use to build a server, and of course X is never enough, so I need to
> decide whether to spend more on 
> cores, memory or disks and in what combination.  As an example I have
> enough to buy either 24 cores 
> and 32 gigs of memory, or 16 cores and 64 gigs of ram, or 16 cores and
> 32 gigs of ram and a bunch of 
> SSDs.
> 
> I am pretty sure that regardless of what I do I will get a substantial
> performance leap, however 
> maximizing that performance leap is still a good thing.
> 
> Any help appreciated.  BTW, I am NOT a DBA so if you give advice like
> "look at the logs", please 
> give specific directions on how to do that.
>