dbcc checkdb()

[masds]

I run dbcc checkdb on one of SQL Servers from my work station, it takes a while then give me an error like network error, the connection broken. I ran it again in the same time I monitor the server using performance monitor, the disk time jumps fairly high when dbcc checkdb is executing, I'm confused here, why this command generates so much I/O?

 

[Catadmin]

Because this command is going through the entire database checking pages and extents (hard disk memory constructs where the data is kept) to see what your usage is and if there is any corruption. There is bound to be a lot of I/O since it's doing what you asked it to do.

If you've got it set to do repair, it might also be deleting and rewriting information as well as reading it.



Catadmin - MCDBA, MCSA
"Just because I'm paranoid doesn't mean the universe *isn't* out to get me!"

 

[masds]

So it really need to run at a low traffic time?

 

[masds]

I need to be aware of the grownth speed, then I can avoid the backup failure. Can I use this command to estimate the grownth speed of the database?

 

[Catadmin]

The command itself doesn't estimate anything, but if you run it at regular intervals, you can get an idea of growth speed. If you do this, though, make sure you document what the last growth amount was and run it at consistant intervals so you can do your averaging.

And yes, you'll want to run it at low traffic times.



Catadmin - MCDBA, MCSA
"Just because I'm paranoid doesn't mean the universe *isn't* out to get me!"