[Linux-cluster] GFS i/o Request size

[Maciej Bogucki]

Mahmoud Hanafi napisał(a):
> 
> 
> It seem that GFS likes to do all I/O in 512KB sizes. Is there a way to
> increase this? I like to do I/O sizes of 1024 or 2048KB.
> 
Hello,

First of all linux kernel breaks IO into pages, and the default page
size is 4K. Second You have to set blocksize for filesystem and default
for GFS is 4096(65536 maximum). Third You have segment size for You SAN
storage - for IBM DS4700 You can set from 8KB to 512KB, and here for
every I/O storage read/write this size od data. If it is clear for You,
which value You want to tune?

Best Regards
Maciej Bogucki