Re: Scalable Performace - Inserts/Updates

On Fri, 22 Dec 2000 19:41:27 GMT, Joel Garry <jgarry_at_my-deja.com> wrote:

>
>Time to fire Nuno! (Just kidding, he 'fessed up! :-)
>

thanks, Joel! Got fired long ago.... ;-D

>I won't. I've got a situation which works ok now, but eventually will
>scale. I have the redo logs on the local disks. However, the data
>files are on a humungo SANS. The thing that is strange - the SANS is
>over fibre, and is quite a bit faster than the local disks. So should
>I move them there? My head says yes, my gut says "huh? Network
>faster than local disk?"
>

Not surprised. Those fibre connections are wickedly fast. Another thing you'll find is the SANS probably has an absolutely ginormous battery-backed cache, making for incredible throughput.

Dunno what your uptime constraints are, but on face value I'd go for the SANS. Here is what I'd do:

• create "devices" for each redo log file.
• mount them as file systems, one for each redo log file.

This will give you max cache access for the redo logs, backed by battery. Only thing faster than that would be a file system mounted on local memory! And I've got a feeling you wouldn't be getting too many failures in that kind of hardware. Those things are more reliable than your local disks...

I think the days of native disks are gone. Most of the optimisations and features for that sort of environment nowadays cannot be justified. These boxes are totally dedicated to manage the disks and they do a darn good job of it. Personally, I like the idea of isolating disk-spread and optimisation from the design of the database. Most of my clients run EMCs. I just recommend basic tablespace spreading (by size). The disk-level optimization I now do at the EMC box and file system layer and leave the database alone. Most of the time it's third-party software anyway, with "locked-in" tablespace names...

Anyways, 'nuff ranting. Merry Christmas and a Happy millenium to youse all. Logging off for the Christmas break...

Cheers
Nuno Souto
nsouto_at_bigpond.net.au.nospam
http://www.users.bigpond.net.au/the_Den/index.html Received on Sat Dec 23 2000 - 05:31:46 CST