Pete is exactly correct here. The four core POWER6 unit that I have in a mobile rack (currently on it's way to COMMON) is a perfect example. It has the very last generation of IOPless large cache SCSI controllers one for 12 drives in an 0595 and and 24 drives in an EXP24. With VIOS as the host those disks crawled. Loading partitions on it was slow. Performance was reasonable running on it because of sufficient arms and little write activity.

Reloading to IBM i 7.1 as the host they do Scream. Remember IBM i hosted disks get formatted with CRTNWSSTG not when you add to the ASP so that right there saves an hour per LPAR when building and everything is quicker all around.

Remember that VIOS is based on AIX and they never did the amount of internal disk work that IBM i has done. As a consequence drivers and performance of internal disk was never a focus for them, they just go SAN.

- Larry "DrFranken" Bolhuis

On 4/26/2014 8:05 AM, Pete Massiello - ML wrote:

I think to Rob's point on hosting internal disk, has something to do with the disk controller
> for internal vs external. <snip> the large cache disk controllers for internal disks, which
>don't perform as well under VIOS as they do under IBM i. They scream under IBM i.

Pete Massiello
iTech Solutions

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