The 2 GiB ext2fs limit has been removed.

IDE disk drivers however currently do not support more than 2^28 sectors, i.e. 128GiB.

The gnumach AHCI disk driver supports up to 2^48 sectors, i.e. 128PiB, but the device interface supports only 2^32 sectors, i.e. 2TiB.

You can have a bigger disk, you just should not put disk partitions beyond these limits for the drivers to be able to read from them.