Le 14/12/2015 21:27, Austin S. Hemmelgarn a écrit : > AFAIUI, the _only_ reason that that is still the default is because of > Mutt, and that won't change as long as some of the kernel developers > are using Mutt for e-mail and the Mutt developers don't realize that > what they are doing is absolutely stupid. >
Mutt is often used as an example but tmpwatch uses atime by default too and it's quite useful. If you have a local cache of remote files for which you want a good hit ratio and don't care too much about its exact size (you should have Nagios/Zabbix/... alerting you when a filesystem reaches a %free limit if you value your system's availability anyway), using tmpwatch with cron to maintain it is only one single line away and does the job. For an example of this particular case, on Gentoo the /usr/portage/distfiles directory is used in one of the tasks you can uncomment to activate in the cron.daily file provided when installing tmpwatch. Using tmpwatch/cron is far more convenient than using a dedicated cache (which might get tricky if the remote isn't HTTP-based, like an rsync/ftp/nfs/... server or doesn't support HTTP IMS requests for example). Some http frameworks put sessions in /tmp: in this case if you want sessions to expire based on usage and not creation time, using tmpwatch or similar with atime is the only way to clean these files. This can even become a performance requirement: I've seen some servers slowing down with tens/hundreds of thousands of session files in /tmp because it was only cleaned at boot and the systems were almost never rebooted... I use noatime and nodiratime on some BTRFS filesystems for performance reasons: Ceph OSDs, heavily snapshotted first-level backup servers and filesystems dedicated to database server files (in addition to nodatacow) come to mind, but the cases where these options are really useful even with BTRFS doesn't seem to be the common ones. Finally Linus Torvalds has been quite vocal and consistent on the general subject of the kernel not breaking user-space APIs no matter what so I wouldn't have much hope for default kernel mount options changes... Lionel -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
