** Description changed: [Impact] autofs service in xenial takes extremely long time since it parses the mount table /etc/mtab in contained_in_local_fs() to determine if the mount patch would be created on a local file system, that means startup process will read /etc/mtab for every mount, so the performance is extremely low. The customer is complaining about this point, we need to backport the following upstream patch. https://git.kernel.org/pub/scm/linux/storage/autofs/autofs.git/commit/?id=67e7d613a4b09eeffc57ab44a7acb52027d897b2 This fix patch removes contained_in_local_fs, and use fs.f_type in is_remote_fstype() to determine if the mount patch would be created on a local file system instead. [Test Case] * Create an autofs direct mount map with large direct mappings (eg: 8k), below is the test script I used. echo "/- auto.direct --timeout 60" >> /etc/auto.master END=8000 for i in $(seq 1 $END); do echo $i; echo "/test/samba/test"$i" -fstype=cifs,rw,username=hua,password=password ://192.168.99.169/share" >> /etc/auto.direct; done * Start autofs service to see if it will take too much time, below is my result before/after applying the fix patch. root@node1:~# time service autofs start real 3m5.481s user 0m0.256s sys 0m0.080s root@node1:~# time service autofs start real 0m0.833s user 0m0.000s sys 0m0.004s [Regression Potential] * We are well aware of the principle of this fix patch - avoiding parsing the mount table to improve startup time, so seems infinitely better for all cases. * This fix from upstream has been backported into Redhat as well, and both me and customer have positive test results with automount start timings. * What releases to fix $ git tag --contains 67e7d613a4b09eeffc57ab44a7acb52027d897b2 release_5_1_2 $ rmadison autofs5 [...] - autofs5 | 5.1.1-1ubuntu3 | xenial | all - autofs5 | 5.1.1-1ubuntu3 | yakkety | all - autofs5 | 5.1.2-1ubuntu1 | zesty | all - autofs5 | 5.1.2-1ubuntu1 | artful | all + autofs5 | 5.1.1-1ubuntu3 | xenial | all + autofs5 | 5.1.1-1ubuntu3 | yakkety | all + autofs5 | 5.1.2-1ubuntu1 | zesty | all + autofs5 | 5.1.2-1ubuntu1 | artful | all + + $ rmadison -u debian autofs5 + autofs5 | 5.1.2-1 | unstable | all Only Xenial and Yakkety are affected since Zesty and Artful already has the upstream fix because it's version 5.1.2. + + Debian unstable also has the fix already. [Other Info] * Redhat [1] also already backported the following patch, see: https://bugzilla.redhat.com/show_bug.cgi?id=1440769 * This mailing list also discussed this problem, see: http://www.spinics.net/lists/autofs/msg01161.html
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1686679 Title: [SRU] Ubuntu16.04 : autofs takes extreamly long with large number of direct maps To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/autofs5/+bug/1686679/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
