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I attempted to install Ubuntu 17.04 after verifying I have a good ISO in a Virtualbox (v.4.3.36) VM running on a Ubuntu 14.04.5 LTS host today (intending to install over top of a Semplice64 VM installation I still had lying around) Much to my surprise I received the warning shown below:

enter image description here

Apparently I need at least as much space as I have. That would seem ok on the surface, however my options are quit and back. and I don't even get the option for manual partitioning.

Digging a bit deeper, The directory shows a VDI disk of 8.6 GB in size which appears to agree with what I see above. Why don't I get the option to install?

Elder Geek
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1 Answers1

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It appears that the problem is related to overhead in the structure of the .VDI disk image reducing the space available for data. According to an old post that I found here on how VDI files are structured:

All VDIs essentially have the same structure. The VDI has four sections:

1) A Standard header descriptor [512 bytes]

2) An image block map. If the (maximum) size of the virtual HDD is N MByte, then this map is 4N bytes long.

3) Block alignment padding. The header format allows for padding between the image block map and the image blocks, and (as of version 1.6.2) the CreateVDI function adds padding after the map to ensure that the first image block begins on a 512byte sector boundary. Since the allocation unit on both NTFS and Ext3 file systems is 4096 bytes, you will therefore get slightly better performance (typically a few %) if you make your VDIs (1024N – 128) MByte long.

4) Up to N x 1MByte image blocks.

So according to this, I'm losing 512 bytes for the header descriptor + 4x8600 bytes for the image block map (another 34,400 bytes) + padding to insure that we end up at a 512 byte sector boundary which by my calculations is another 416 bytes. This clearly puts me in excess of 35,000 bytes short of the minimum.

Elder Geek
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