You are correct in your assumption; the BMR server components (main, boot and file server) can only be installed on AIX, SunOS or HP-UX. This is mostly due to Windows? lack of support for a true network boot (bootp or bootstrap protocol). As far as set up time on AIX in a recovery situation, that particular operating system offers a nice feature called MKSYSB (make system backup). This feature allows you to create a bootable image of your system while the system is running. In other words, AIX is capable of creating a backup of its own system data on a media that you can boot from and restore following a disaster.

Using that technology, you could restore your BMR server from a previously created MKSYSB bootable media at the same time you are rebuilding and restoring your NetBackup server. You would run a new MKSYSB every time you update the BMR server such as when a new set of OS files are created for a BMR client (known as SRT or shared resource tree).

The main limitation to this approach is the capacity of the media used to create the MKSYSB. A single SRT can take up to 400MB of space on the BMR server and a different SRT is required for each OS platform and version. Depending on the number of different OS versions in your environment, you could easily end up creating a BMR server for which a single MKSYSB image exceeds the capacity of many removable media. The choice of media and availability of a similar device at your recovery site are two aspects to consider as well.