perl - MongoDB verify if fsync is working -

i perform fsync() operation in mongodb, returns immediately. doesn't appear have done anything. how verify if data has indeed been flushed disk @ all?

note: set syncdelay 0 means writes won't automatically fsync'ed every 60 seconds.

my actual command using perl driver:

$connection->fsync({async=>1}); 

thanks.

if don't want fsync return immediately, can remove async option , become blocking operation.

but if don't want blocking, can use db.currentop shell query current state of fsync.

if want information perl, can use technique outlined in this answer. unfortunately there's no convenient way directly via run_command.