Of the servers listed, the only servers that the image disc set will create a 4GB active partition on are the MCS7827 and MCS7837. The other three configurations (MCS7847 and the two versions of ML570G1) will have an 8GB system partition imposed on them because they have multiple arrays to absorb applications, logs and databases.
The intent with the first two servers is to preserve as much space as possible in the second partition for applications plus transaction logs plus Exchange databases (if installed) plus free space equivalent to 110% of the size of a single Exchange database at its largest possible size given the use of the G.711 codec by the maximum possible number of users with thirty minutes of storage each. That space to be reserved for usage of Microsoft's <> utility on that database.
Clearly, this is a worst case accomodation. There is no way to alter the preconditions of the creation of partition size in this image set. In response, it is recommended to install some or all applications and definitely any logs and databases into the second partition, reserving the system partition just for the OS and its pagefile.
If you were to opt instead to build a server piece by piece rather than using the image, it would not be recommended to have one large partition on the boot array. If that disk array was not frequently maintained and were to fill up the OS would cease to be bootable. This is one of the advantages of using multiple partitions in a single disk or single RAID-1 configuration.
