[AccessD] Needs analysis

Jim Dettman jimdettman at verizon.net
Sun Jun 20 17:22:53 CDT 2010


John,

<<I have lost the occasional drive, and with a dedicated raid controller you
just replace the drive 
and the controller starts to rebuild the raid.  Raid 6 allows you to lose
two drives and still 
rebuild.  Raid 5 causes you to lose the shooting match if you lose 2 drives.
I have massive amounts 
of stuff here, and it does not belong to me.  I cannot afford to be cavalier
about the system.>>

  I wasn't suggesting that you be cavalier about it.  Certainly no one here
knows your exact situation or how you have everything configured.  I was
just suggesting you weigh the risk vs the benefit.  Certainly if your
requirements are such that you can afford zero down time, then RAID is
called for.

  But often one backs into a situation slowly without re-evaluating why they
are there in the first place.  For example, how much time does it cost you
to rebuild the array when a drive drops vs restoring from a backup?  And
keep in mind that often while a rebuild is in progress, through put is
severely degraded.  You might be ahead of the game if you simply restored
backups.  And of course if you had physical volumes to play with, then you
could control where databases were being placed and gain even more
performance.

  RAID is great for zero down time, but you do pay for that benefit in many
ways.   And since performance seems to be the over riding goal here, RAID
may be costing you more then it's worth.

Jim. 
-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of jwcolby
Sent: Sunday, June 20, 2010 1:36 PM
To: Access Developers discussion and problem solving
Subject: Re: [AccessD] Needs analysis

Jim,

It's not one database it is dozens of databases, the smallest of which is 20
to 30 gigabits.  I have 
a 2 gig volume that is the database storage, another 2 gigs which are online
backups, another 2 gigs 
which are order storage (spreadsheets and raw text files going in / out of
the database), a raid one 
which is the boot drive and a raid 0 which is the temp database.  Oh, and
the one gig offline backup 
for rotation (soon to be 2 gigs).

I have lost the occasional drive, and with a dedicated raid controller you
just replace the drive 
and the controller starts to rebuild the raid.  Raid 6 allows you to lose
two drives and still 
rebuild.  Raid 5 causes you to lose the shooting match if you lose 2 drives.
I have massive amounts 
of stuff here, and it does not belong to me.  I cannot afford to be cavalier
about the system.

In the 5+ years I have been doing this stuff I have never had a single
instant where the data was 
not available - and by that I really mean where I could not just move the
entire thing to another 
system if necessary.

I build my own systems and I have had times where one of my two servers at a
time was being 
upgraded, new motherboard and so forth but if push came to shove I could
always just swap the raid 
array to the other machine and be back up in a matter of an hour or so.  I
credit that reliability 
to RAID.

All of that said, I am actively evaluating using SSDs for two specific
databases which are kind of 
the center of the universe.  It will probably be raid 0 in order to get
gigantic read speed, and I 
will just have to make sure that I have a backup available at all times.

 >  And I would agree Mark's point; your off in the wild blue yonder.  I
think you'd find better 
answers at SQL central or another SQL specific forum rather then the here.

I actually posted this thread to AccessD by mistake.  My intention was to
post to the SQL Server 
group, which I did when I realized that I had posted to AccessD.

OTOH I have posted about the "database from hell" in the past and some here
might find it 
interesting how that has morphed into an entire business.

I am looking at building out a new "latest gen" server to host this
business.  It appears that I am 
going to have a budget of around $6,000.  That wouldn't touch a Dell or HP
but since I build my own 
it is "just barely" enough to do what I am looking to do.  For that I am
hoping to get:

1) A dual socket server grade motherboard:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131643

2) 32 gigs or perhaps even 64 gigs of registered, ECC ram.

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010170541+10521
29233+1052323986&QksAutoSuggestion=&ShowDeactivatedMark=False&Configurator=&
Subcategory=541&description=&Ntk=&CFG=&SpeTabStoreType=&srchInDesc=

3) (two) 8 core AMD chips (though Newegg is out of stock ATM.)

http://www.newegg.com/Product/Product.aspx?Item=N82E16819105266

4) a 4U rackmount case with space for 20 hard drives

http://www.newegg.com/Product/Product.aspx?Item=N82E16811219021&cm_re=4u_rac
kmount_case-_-11-219-021-_-Product

5) an 850 watt supply

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139011

I will then move my existing raid controller and drives in.

I have Windows 2008 x64 and SQL Server 2008 which I will use for this.

I have to make a decision whether to "only" get 32 gigs of RAM and use the
remaining money for SSDs 
or go with 64 gigs or RAM and get SSDs later.  SSDs have not dropped in
price as I would have 
expected, however they have become more mainstream, and I can only hope that
they are approaching 
the knee of the price curve and will start to head downwards.

In any case, I expect to see a significant boost in all around capability
from the new system.

John W. Colby
www.ColbyConsulting.com


Jim Dettman wrote:
>  Why bother to use RAID at all?  Since this is mostly a read only
situation,
> I would not worry too much about loosing a drive because you can just
> reload.
> 
>  I mean ask yourself, when's the last time you lost a drive?  And how long
> would it take you to recover?
> 
>  And I would agree Mark's point; your off in the wild blue yonder.  I
think
> you'd find better answers at SQL central or another SQL specific forum
> rather then the here.
> 
> Jim. 

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