4 ms·

Is there anything like this for / can this be used with AWS?

• rwmj 10y ago
  These kinds of tools use hypervisor APIs that allow you to inspect memory from outside the guest. eg. QEMU's pmemsave command. I would think it's highly unlikely that AWS would want to give out such low-level access, not least because you can do very bad stuff if that access gets into the wrong hands (eg. read "secure" bits of guest kernel memory).
  • jonaf 10y ago
    Thanks. I didn't expect this particular tool would work. I am diagnosing a performance issue on hosts using HVM virtualization (where instead of being better than paravirtualization, it is actually markedly worse); if there was a tool for a guest to on some level provide debug information for itself, I thought it may aid my investigation. Sadly, I suspect even if any such tools exist, Amazon will have disabled their use for all the obvious, managed, multi-tenant reasons.
    • drvdevd 10y ago
      If you can dump the VMs "physical memory" - even from an AWS VM, e.g. using the LiME kernel module (https://github.com/volatilityfoundation/volatility/wiki/Lime-Address-Space https://github.com/volatilityfoundation/volatility/wiki/Lime...) you can still use Volatility and I believe libvmi as well to get some details about what's happening and I don't think it would be possible to disable this technique. Also, this shouldn't interfere with any other guests on the same metal.
    • paulfurtado 10y ago
      Not knowing more about your problem, I'm not so sure that something at the hypervisor level is necessary to see where you're losing performance on HVM, even though it could potentially help. Have you tried using tools like perf, SystemTap, or dtrace inside the VM?
    • abuabdullah 10y ago
      I used to think Paravirtualization must be faster than HVM. At very least for network and I/O.