Question about compactions

[Brennon Church]

Hello all,

As I understand it, a common performance tweak is to disable major 
compactions so that you don't end up with storms taking things out at 
inconvenient times.  I'm thinking that I should just write a quick 
script to rotate through all of our regions, one at a time, and compact 
them.  Again, if I'm understanding this correctly we should not end up 
with storms as they'll only happen one at a time, and each one doesn't 
run for long.  Does that seem reasonable, or am I missing something?  My 
hope is to run the script regularly.

Corollary question... I recently added drives to our nodes and since I 
did this while they were all still running, basically just restarting 
the datanode underneath to pick up the new spindles, I'm fairly sure 
I've thrown data locality out the window, based on the changed pattern 
of network traffic.  If I'm right, manually running major compactions 
against all of the regions should resolve that, as the underlying data 
would all get written locally.  Again, does that make sense?

Thanks!

--Brennon