How can I temporally write a file to the filesystem but actually hold it on RAM?

Question

I have a server that receives a file in a HTTP request, I'd like to make that file available to another process but I don't want the I/O overhead of writing that file to disk.

Are there any directories in linux that are actually mapped to RAM, so the process I start can access a path as is were a normal file?

I know that if I do this in a normal file, then there is a good chance that the file wont actually be flushed to disk because of cache, but that's not what I'm looking for.

Answer 1

There are no guaranteed locations that are backed by RAM, but it's not particularly hard to convert /tmp to be backed by RAM if you have enough of RAM to spare. Given that /tmp is cleaned out on boot anyway, it's an ideal choice for a RAM disk, since data loss due to power loss doesn't matter; the data would have been cleaned on boot anyway.

Answer 2

You can use the following to create a RAM disk (as per these instructions):

mkdir /mnt/ramdisk
mount -t ramfs -o size=512m ramfs /mnt/ramdisk