I don't know enough to comment on the internals of the “mount -t tmpfs" issue, but I verified via clean VirtualBox VM and snapshots that the only difference between success and failure on Ubuntu 12.04 Beta 2 was the above change. On Ubuntu 11.10 in VM with same memory (2048) the change was not needed.
In the original version, "df -h /run/shm" said that 1% was used whereas in the modified version it said that 0% was used. That doesn't seem like a significant difference, so something else must be going on.
Also, could you clarify step 6? Is this *required* for installation or just for performance reasons?
Thanks for all the time you put into creating the 11.x versions of these instructions. We will eagerly await the 12.04 version whenever you have time.
Please see my reply at Re: Ubuntu 12.04 Oracle XE and ORA-00845: MEMORY_TARGET not supported Regarding step 6, as the first paragraph tries to outline, this is mainly for performance reasons as there are confirmed performance issues with Oracle database and ext4. Unfortunately I don't have further details, so using ext3 sounds more reasonable.
I've updated Re: Ubuntu 12.04 Oracle XE and ORA-00845: MEMORY_TARGET not supported
The following could be a possible work around:
mount -B /run/shm /dev/shm
mount --move /run/shm /dev/shm
mount -B /dev/shm /run/shm
Please do not attach anymore 12.04 issues regrading this matter to this howto thread. Thank you.