2.3 - 2.5 upgrade error/ Mysqli statement execute error : Error writing file

I’m upgrading from 2.3 to 2.5 on our apache server. Ran thru most of the steps, moving the old copies of these to the new directory:

db.ini
files/
extra plugins
extra themes

but updating the db fails with this error.

exception ‘Zend_Db_Statement_Mysqli_Exception’ with message ‘Mysqli statement execute error : Error writing file ‘./beomeka/#sql-1415_78b78.frm’ (Errcode: 28)’ in /var/www/html/beomeka/omeka/application/libraries/Zend/Db/Statement/Mysqli.php:214
Stack trace:
#0 /var/www/html/beomeka/omeka/application/libraries/Zend/Db/Statement.php(303): Zend_Db_Statement_Mysqli->_execute(Array)
#1 /var/www/html/beomeka/omeka/application/libraries/Zend/Db/Adapter/Abstract.php(480): Zend_Db_Statement->execute(Array)
#2 [internal function]: Zend_Db_Adapter_Abstract->query(‘ALTER TABLE om...') #3 /var/www/html/beomeka/omeka/application/libraries/Omeka/Db.php(79): call_user_func_array(Array, Array) #4 /var/www/html/beomeka/omeka/application/migrations/20150814155100_storeSessionAsBlob.php(20): Omeka_Db->__call('query', Array) #5 /var/www/html/beomeka/omeka/application/migrations/20150814155100_storeSessionAsBlob.php(20): Omeka_Db->query('ALTER TABLEom…’)
#6 /var/www/html/beomeka/omeka/application/libraries/Omeka/Db/Migration/Manager.php(231): storeSessionAsBlob->up()
#7 /var/www/html/beomeka/omeka/application/libraries/Omeka/Db/Migration/Manager.php(111): Omeka_Db_Migration_Manager->_migrateUp(Object(DateTime))
#8 /var/www/html/beomeka/omeka/application/controllers/UpgradeController.php(49): Omeka_Db_Migration_Manager->migrate()
#9 /var/www/html/beomeka/omeka/application/libraries/Zend/Controller/Action.php(516): UpgradeController->migrateAction()
#10 /var/www/html/beomeka/omeka/application/libraries/Zend/Controller/Dispatcher/Standard.php(308): Zend_Controller_Action->dispatch(‘migrateAction’)
#11 /var/www/html/beomeka/omeka/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#12 /var/www/html/beomeka/omeka/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(105): Zend_Controller_Front->dispatch()
#13 /var/www/html/beomeka/omeka/application/libraries/Zend/Application.php(384): Zend_Application_Bootstrap_Bootstrap->run()
#14 /var/www/html/beomeka/omeka/application/libraries/Omeka/Application.php(77): Zend_Application->run()
#15 /var/www/html/beomeka/omeka/admin/index.php(28): Omeka_Application->run()
#16 {main}

has anyone seen this before or have any ideas? Thanks.

I think that’s often caused by the writable disk space being full.

That was the answer, thanks! Too focused on omeka to check the obvious.