Re: [CentOS] Optimum Block Size to use

On Tue, Aug 18, 2015 at 9:38 PM, Jatin Davey jashokda@cisco.com wrote:

I have a few queries with respect to the block size being set in the system:

1. Is 4k the optimum block size considering the amount of writes / second

the application performs ?

2. How do i find out the optimum block size given the application load in

terms of reads / writes per second ?

3. If there is a better block size that i can use , Can you suggest one ?

4. What are the pros / Cons of changing the default block size ?

On x86, it's effectively fixed at 4096 bytes. There is a clustering option in ext4 called bigalloc which isn't the same thing as block size but might be what you're looking for if you have a lot of larger file writes happening. But this implies CentOS 7 to get this feature.

5. We use ext3 as the file system for the partition which has heavy writes

per second , Should we migrate it to ext4 ? Any pros / cons for it ?

Piles of pros, and no meaningful cons. Just use ext4 with defaults.