[h8mmer]

Hi,

Anyone know what the differences are between SDD and SDDPCM?

The only thing I can see is that PCM uses similar syntax etc to the AIX default PCM (MPIO) and presents hdisk rather than vpaths.

Am in a situation where IBM have specified SDDPCM on a virgin LPAR for attachement to a newly delivered DS8100 but cannot justify why we don't stick with normal SDD (which we use against our existing ESS and are comfortable with).

TIA,
H8mmer

[cdelgadop]

Hi

AFAIK SDD can use load balancing between all vpaths on a storage system like old 2105 Sharks or new DS8100 while the SDDPCM uses an approach similar to that in FastT storage boxes of using one HBA as prefered path and leave another for failover purposes.

For a reason i have not understod yet, SDDPCM is recommended when using IBM SVC devices.

Hope this helps

[h8mmer]

Thanks cdelgadop, I should have also said that we have an SVC cluster sat in the middle of our new fabric which confirms what you have said.

No load balancing is a large sacrifice to make IMO, I'll chase this further with our IBM stg guys and post anything I get back.