ZFS : When resilvering is in progress, ZIL disk removal is restarting the resilvering process .

[Pawan Prakash Sharma]

This is happening because as part of clean up the vdev namespace
(spa_vdev_remove_from_namespace) after removing ZIL disk, we reopen
(vdev_reopen) all the vdev, which checks if resilvering is needed for a
leaf vdev, if it is needed, it restarts the resilvering. It doesn't check
if resilvering is already going on or not. So if resilvering is already
in-progress, it will start it from the beginning.

My question is, why we are not checking for dsl_scan_resilvering (we do
this in spa_load_impl) in vdev_open? What will be the side effects if we
put this check while opening the vdev?


Let me know if I am missing anything.

vdev_open() :-

  /*
  * If a leaf vdev has a DTL, and seems healthy, then kick off a
  * resilver.  But don't do this if we are doing a reopen for a scrub,
  * since this would just restart the scrub we are already doing.
  */
  if (vd->vdev_ops->vdev_op_leaf && !spa->spa_scrub_reopen &&
  vdev_resilver_needed(vd, NULL, NULL))
  spa_async_request(spa, SPA_ASYNC_RESILVER);


Regards,
Pawan.