I wish to allocate vSwap memory to my OpenVZ containers. Where does OpenVz get the vSwap memory from? If the host were to run out of physical RAM, would the host start to use its own normal swap memory?
I ask this as I am using SSDs in our host server, which while not as fast as proper RAM, are still loads faster than spindle disks, so using normal swap space from these SSDs wouldn't be the worst thing in the world.
Many Thanks
This a standard host swap area exactly where you have configured it. vSwap - is just an option to set limits separately for RAM/SWAP on per-container basis. This option was not available in the past and one had to set joint limit RAM+SWAP called VMGARPAGES (that is amount of virtual memory).
PS. I would warn you against active using of SSD-based swap due to restricted number of write cycles for flash memory. Especially in RAID setup where trim option expected to be not available.