What is /dev/shm for ? How is it created ?

[AJenks]

I have created partitions as per best practice documentation, however when I view the partitions using df and compare the output with one of my existing ESX servers (that was supposedly installed using the same documentation), it is only 50% the size on the newly installed server. Does this relate to a partition I am manually creating and if so, which one ? or is it something created during install - why the difference ? Disk sizes are the same between machines, processors and RAM are different.

[ian4563]

It is a temp file system mapped to system RAM. It's part of most linux distributions and is mounted in your fstab file, but I can't see it being of any use in VMWare. They are different sizes on your servers because the amount of RAM is different. In short, don't use it and don't worry about it.

[Sangokan]

/dev/shm is created by redhat, it is a temporary file and it is not the swap