[sheepdog-users] joural

[Liu Yuan]

On 12/20/2012 07:29 PM, Valerio Pachera wrote:
> We made sure that moving journal to a dedicated device increase
> cluster performance.
> What I didn't get yes is: *what size give to journal?*
> 
> The bigger the better? Or does it need to be a precise size?
> 
> PS: I noticed the the "journal device" make more i/o than the "sheep
> dog" device, something like 20%sheepdog device 40%journal device).
> 
> Thank you
> 

The size of journal file will affect node when to commit the data to
disk in the journal file.

The bigger journal file, you'll have
 pros: less rounds of committing
 cons: longer time for one committing process (VM will be slowed down in
the process of committing)

To get the balance, I think 256M~512M is good enough.

Thanks,
Yuan