I am running drush -vd updb --yes || exit 1
to upgrade D6 to D7 then I got this error several times atleast.
Bootstrap to phase 0. [0.01 sec, 4.79 MB] [bootstrap]
Drush bootstrap phase : _drush_bootstrap_drush() [0.01 sec, 5.08 MB] [bootstrap]
Cache HIT cid: 5.0-commandfiles-0-eae08ebb5299072299ae95f485024c57 [0.02 sec, 5.09 MB] [debug]
Bootstrap to phase 0. [0.06 sec, 11.02 MB] [bootstrap]
Bootstrap to phase 2. [0.08 sec, 11.03 MB] [bootstrap]
Drush bootstrap phase : _drush_bootstrap_drupal_root() [0.09 sec, 11.03 MB] [bootstrap]
Initialized Drupal 7.14 root directory at /var/www/vhosts/git/html [0.12 sec, 15.06 MB] [notice]
Drush bootstrap phase : _drush_bootstrap_drupal_site() [0.12 sec, 15.07 MB] [bootstrap]
Initialized Drupal site default at sites/default [0.12 sec, 15.07 MB] [notice]
Cache MISS cid: 5.0-commandfiles-2-d0694fde84f442a7d33c2119cff575f2 [0.13 sec, 15.07 MB] [debug]
Cache SET cid: <em class="placeholder">5.0-commandfiles-2-d0694fde84f442a7d33c2119cff575f2</em> [0.27 sec, 15.09 MB] [debug]
Found command: updatedb (commandfile=core) [0.28 sec, 16.05 MB] [bootstrap]
Segmentation fault
Any idea what is segmentation fault is?