Re: What constitues a VLDB?

In article <33490F34.31B8_at_hk.super.net>, infoage_at_hk.super.net says...
> James F. Valenti wrote:
> >
> > Hi!
> >
> > DBA's have to do extra work when planning and configuring a VLDB.
> > What, in your opinion, establishes a database as being Very Large these
> > days?
> > Is it size alone? Or is it a combination of size, level of concurrency,
> > transaction rate?
> > If it's size alone, where is the threshold? 10 GB, 100GB, TB's?
>
> Every problem applying to normal DB are applicable to VLDB. Same old
> story. But with VLDB, just more measurement needed to undertaken.
> Like Backup and Restore Strategy, small or large or VL, you have to do
> that, but just do it in different way. Job and Task is same, the
> way of doing that is totally different.

Very true. A good DBA will use the same techniques and strategies on a 5Gb database as those that are 100Gb or 300Gb. The frequencies may be different, the parameter values may be smaller and some ologies (methods of ologies) may be different for backup, failover or management strategies. But, the same thought processes are used.

This is why I feel there is not much weight in finding DBAs that have managed your database size or large exactly. Meaning, if a DBA says he/she has worked with 80Gb databases, and yours is 150-200Gb, don't freak out and think this person can't handle it. A valid quesion to ask during an interview is "What is the largest database you have managed?" But, it should be used to determine how the candidate thinks and what types of environments they have worked in.

How do you break down databases to determine what is a VLDB? The answer to this question is always relative. To this day, I still see NT people claiming NT is this and that because they have a 30Gb Oracle database with 100 users. (NOTE: I like NT also, just using it as an example). Relative to them, that 30Gb is a VLDB! I usually break VLDB down into OLTP (typically....let me say that again, typically NOT over 300Gb) and Data Warehouses. Your average OLTP database is probably somewhere between 50 - 300Gb (there are exceptions and that is a wide margin) and your Data Warehouse is usually 200Gb to terrabytes. The importance noted is the differences used to manage these two environments. Massive amounts of data with batch updates and very read intensive vs. OLTP systems with lots of inserts, updates, deletes. Different environments that require different mangement tools and configurations.

The objective is to find the candidate that thinks correctly and knows how to apply the differences to both environments.

• n

-- 
Neil Greene				 
Senior System Engineer / Oracle DBA
MCI Systemhouse, Inc. 		
email: ngreene_at_laoc.SHL.com