I have an automated script in php to check my FB1.5 database health and email me the results. One of the things i am interested in is whether the shadow file is still active. I am running the ibase_db_info command and also reading the shadow file name from the RDB$FILES system table but this does not seem to detect when the shadow file is unavailable - sometimes when the drive on which the shadow resides (an iscsi target) goes down, the shadow count remains at 1 and sometimes it increases to 2 rather than going down to 0. The shadow file name is not erased from the system tables when the shadow drive is unavailable.

Any ideas on why this technique does not work or another way to check whether the shadow is still active ?