Yes it does if you have a journaling filesystem. For example, fsync/fsyncdata calls get special treatment on filesystems like ext3. When the filesystem containing the files on which fsync is called and it is mounted data=journal, those writes hit the filesystem journal first after which the fsync gets to say OK. After that the kernel will write from the journal to the rest of the disk at its leisure.
I thought file system journals like ext3 were just used for the file system metadata? inode allocations and directory updates and so forth, not actual user data?.
If I understand what you're suggesting, if I write 200MB of data then fsync, my -data- is written to the journal, then later written to the actual file system?
anyways, I seriously doubt we could convince operations at our manufacturing facilities to add ramdrives to their mostly HP servers. I don't even know if they'd fit in the blade servers most commonly used.