Is it possible to change sunit of log section post-mkfs

[Michael Weissenbacher]

Hi Dave!

>>
>> What i want to achieve is to set the log sunit to the maximum possible
>> of 64 blks (=256KiB).
On 2015-11-03 20:11, Dave Chinner wrote:
> 
> Why? Is there a performance problem with the default setting?
> 
I am seeing very bad performance of "rm" on this file system. Of course
I know that RAID-6 is kind of a worst case setup for that workload. But
I was hoping that aligning the log correctly plus increasing the stripe
size would help. Wouldn't the file system write more of the log at once
with a bigger sunit size; resulting in fewer RMW cycles?

I am already using delaylog, inode64, nobarrier to mount the fs;
lazy-count=1.

Maybe moving to an external log would be the best option?

tia,
Michael