The Nokia N900 has 32 GB eMMC and 256 MB NAND non-removable storage. Additional storage is available via a hot swappable microSDHC card socket, which is certified to support up to 16 GB of additional storage. The microSDHC card can be formatted with a supported file system such as ext2, ext3, FAT16 and FAT32.

The 32 GB eMMC is split into 3 partitions:
2 GB as ext3 mounted to /home