max_dbc_pct

[navin]

Hello All,
Can some one please let me know lil more info about max_dbc_pct
Thanks much in advance

[Tim Nelson · Accepted solution]

sets the filesystem buffer cache to a percent of total ram.

by default it is 50%. This is way too much and is a BAD default.

for a database system tune to around 2%-3% ( around 500-800mb )

you will also need to modify min_dbc_pct suggest 1% ( or around 100mb)

% obviously depends on how much ram you have.

[James R. Ferguson]

Hi Navin:

This kernel paramter is used (though 11.23) to govern the upper limit size of the Unix buffer cache:

http://docs.hp.com/en/B3921-60631/dbc_max_pct.5.html

The 'syncer' daemon runs every 30-seconds to flush modified buffers to disk from this cache.

On 11.31 and later, this parameter is replaced by the 'filecache_max' parameter:

http://docs.hp.com/en/B2355-60130/filecache_max.5.html

Regards!

...JRF...