get_directory_size takes too long on NFS with TBs of data

[bozicm]

Hello,

core get_directory_size function is used classes/task/report_async.php, which uses linux command du. In our setup we have use north of 30TB of moodledata (not including course backups). The moodledata is mounted via NFS which then makes it near impossible to calculate total with du because of iowait. Wouldn't it make sense to just use df on mountpoint in such case?

[danmarsden]

pull requests welcome :-) - keep in mind the reason it uses du is because Moodle has a "pathtodu" config setting - if we swap out to using df it should be optional as not all servers (eg windows etc) will have a df option, but also may have other things mounted on that same disk.