During the conversion of a Redhat ES 4 (Nahant) physical server to an esx3.5i host I was having repeated failures after around 15 minutes.
From vmware-converter-agent.log I found this error “/sbin/mkfs.ext3 did not finish producing output after 300 seconds“.
An researched this to find that there is a hard coded limit on the length of time allow for the conversion process to format the target vm file system.
Given that the source image was 600GB and the target server was a recycled PowerEdge 850 about 5 years old – I guessed that the speed of the machine and the size of the file systems might be a factor.
Luckily I was able to reduce the size of the target VM to the amount that was actually in use on the disks – around 400GB and the conversion proceeded successfully.
I noted that this problem does not appear to have been addressed since there have been no later releases of the specific linux converter.
So if you come across this – be prepared to shrink the target size and perhaps re convert on the target server to resize – or perhaps try a faster host with decent processors and IO !!