[Lustre-discuss] Clarification on DDN performance best practices

[Paul Cote]

The Lustre manual (DDN tuning section) suggest the following:

 > On the S2A 9500 and 9550, we measured significantly better 
performance with 2 tiers per LUN

I've seen conflicting statements regarding this. Are you saying that 2 
tiers should be the max? Or is it advantageous to create OSTs that span 
many more? I've seen indication of up to 12 tiers to maximize write 
performance. Any insight would help.

Also, when creating LUNs on a DDN to be use exclusively for OSTs, does 
in make sense to use a disk block size of 4K (instead of 512bytes) since 
the standard block size for luster is also 4K.

Thanks,
/pgc