Omeka has encountered an error

Zend_Db_Statement_Mysqli_Exception

Mysqli statement execute error : Error writing file '/var/tmp/MYVjXNrm' (Errcode: 28)

Zend_Db_Statement_Mysqli_Exception: Mysqli statement execute error : Error writing file '/var/tmp/MYVjXNrm' (Errcode: 28) in /var/www/html/digital/application/libraries/Zend/Db/Statement/Mysqli.php:214
Stack trace:
#0 /var/www/html/digital/application/libraries/Zend/Db/Statement.php(303): Zend_Db_Statement_Mysqli->_execute(Array)
#1 /var/www/html/digital/application/libraries/Zend/Db/Adapter/Abstract.php(480): Zend_Db_Statement->execute(Array)
#2 /var/www/html/digital/application/libraries/Omeka/Db.php(79): Zend_Db_Adapter_Abstract->query('SELECT `items`....', Array)
#3 /var/www/html/digital/application/libraries/Omeka/Db/Table.php(647): Omeka_Db->__call('query', Array)
#4 /var/www/html/digital/application/libraries/Omeka/Db/Table.php(281): Omeka_Db_Table->fetchObjects(Object(Omeka_Db_Select))
#5 /var/www/html/digital/application/controllers/helpers/Db.php(59): Omeka_Db_Table->findBy(Array, 50, 1)
#6 /var/www/html/digital/application/libraries/Omeka/Controller/AbstractActionController.php(128): Omeka_Controller_Action_Helper_Db->__call('findBy', Array)
#7 /var/www/html/digital/application/controllers/ItemsController.php(176): Omeka_Controller_AbstractActionController->browseAction()
#8 /var/www/html/digital/application/libraries/Zend/Controller/Action.php(516): ItemsController->browseAction()
#9 /var/www/html/digital/application/libraries/Zend/Controller/Dispatcher/Standard.php(308): Zend_Controller_Action->dispatch('browseAction')
#10 /var/www/html/digital/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#11 /var/www/html/digital/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(105): Zend_Controller_Front->dispatch()
#12 /var/www/html/digital/application/libraries/Zend/Application.php(384): Zend_Application_Bootstrap_Bootstrap->run()
#13 /var/www/html/digital/application/libraries/Omeka/Application.php(73): Zend_Application->run()
#14 /var/www/html/digital/index.php(23): Omeka_Application->run()
#15 {main}