On Wed, Jan 8, 2020 at 1:43 PM Valentin Vidić <vvidic@valentin-vidic.from.hr> wrote:
On Wed, Jan 08, 2020 at 01:33:21PM -0500, Jeffrey Walton wrote:
I believe this is the relevant part from the Pastebin:
readlink("/swapfile", 0x7ffefb4c0810, 4096) = -1 EINVAL (Invalid argument) stat("/swapfile", {st_mode=S_IFREG|0600, st_size=2147483648, ...}) = 0 open("/swapfile", O_RDONLY) = 3 read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 65536) = 65536 close(3) = 0 swapon("/swapfile", 0) = -1 EPERM (Operation not permitted)
Yes, the swapon call fails with this error. You can check the kernel name with uname -a, but it probably runs a custom build and you can't reboot with a different one to enable swap functionality.
It looks like this is coming from the OpenVZ folks. They feel a swapfile would negatively impact performance, so it is disabled. (I'm not sure how a DoS is considered a good result, given an OOM kill just about always knocks out MySQL). Jeff