Great mail, Stan
Another trick: you can save storage (both space & iops) using mdox and compression. CPU power is far cheaper than iops , the less data you read/write, the fewer iops. You can use gzip,bzip2 or even LZMA/xz compression for LDA. If you also use Single Instace Storage and Alternate (cheap) storage for old mail, you can save a lot of money in storage. Also consider using mdbox + ssd for indexes (hp storevirtual VSA+ a couple of ESXi with ssd disks will give you real-time replicated ssd iscsi lun for indexes) Just my 2 cents. Regards Javier