virtualbox.org

Hi,

I have read an article about the use of the ContigFileAllocSize registry key, helping to avoid fragmenting disks (see here: http://www.dev-toast.com/2007/02/22/inc ... fficiency/ ). The author says that this tweak should not be used in a guest, as it may corrupt the vdi file on the host. However, the article is more than 2 years old and I guess this issue might have been solved in the meantime. Has someone already tried this ?

I have the feeling, if it works, that the benefits of this tweak might be bigger in a virtual disk (where you don't care too much about leaving empty gaps, if they are not allocated in the vdi).

(If nobody as ever tried it, I will test it, with a copy of my favorite vdi and on a partition which I would accept to see corrupted).

NTFS and "Avoid Defragmentation" are an oxymoron

You just need to defragment regularly and keep your NTFS partitions less than 75% full. Also if you are using the default Windows defrag, it's prett stupid. It won't move a file unless it has a sufficient contig space to put it in. Hence you can get a file with a 1,000 fragments that it won't move and this chops your FS into a 1,000 small bits. So also try the MS Systinternals tool contig which is at least smart enough to realise that 2 big fragments is a lot better then 1,000 small ones.

Also the VDI allocation page size is 1Mb so this change won't help in terms of host VDI sizing.