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[Avishay Traeger <avishay@xxxxxxxxx>]

Public bug reported:

On a system with no Fibre Channel (FC) HBAs, each call to
get_volume_connector() in virt/libvirt/driver.py will result in
retrieving the FC HBA info.  This is because the code looks like this:

self._fc_wwnns = None
self._fc_wwpns = None
...
if not self._fc_wwnns:
    self._fc_wwnns = libvirt_utils.get_fc_wwnns()
...
if not self._fc_wwpns:
    self._fc_wwpns = libvirt_utils.get_fc_wwpns()

In a system with no HBAs, the two utils functions return empty lists.
Therefore we will go into these ifs on every call.  The if statements
should be re-written as "if self.foo is not None".

I have seen busy systems where these two calls add 800ms to each attach
call!

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1406484

Title:
  Fibre channel info retrieved on each call to get_volume_connector

Status in OpenStack Compute (Nova):
  New

Bug description:
  On a system with no Fibre Channel (FC) HBAs, each call to
  get_volume_connector() in virt/libvirt/driver.py will result in
  retrieving the FC HBA info.  This is because the code looks like this:

  self._fc_wwnns = None
  self._fc_wwpns = None
  ...
  if not self._fc_wwnns:
      self._fc_wwnns = libvirt_utils.get_fc_wwnns()
  ...
  if not self._fc_wwpns:
      self._fc_wwpns = libvirt_utils.get_fc_wwpns()

  In a system with no HBAs, the two utils functions return empty lists.
  Therefore we will go into these ifs on every call.  The if statements
  should be re-written as "if self.foo is not None".

  I have seen busy systems where these two calls add 800ms to each
  attach call!

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