Regular registration for the Lustre User Group 2017 conference ends on May
1st. Be sure to register by this date to obtain significant savings from the
late registration price. The full conference agenda and registration are
available at http://opensfs.org/lug-2017/.
This year's conference will feature the latest Lustre developments and
special events for connecting with your colleagues, including an opening
reception sponsored by DDN at IU's Cyberinfrastructure Building, Dinner and
a Movie (Breaking Away) at the historical IU Auditorium sponsored by Intel,
and a pub crawl sponsored by HGST/WARP.
Registration will be capped at 200 attendees. Only a few late registrations
will be accepted- and only if we have not reached capacity.
The hotel block for LUG 2017 attendees will expire soon. A few rooms are
still available at the IMU, but be sure to book by the hotel reservation
deadline, April 25, 2017 at 11:59pm EST.
Questions about the conference? Contact pti(a)iu.edu <mailto:email@example.com>
We look forward to seeing you in Bloomington!
This past weekend we filled up our change logs as reported by: "changelog failed: rc=-28"
Looking at the changelog_users showed the following:
# cat /proc/fs/lustre/mdd/scratch-MDT0000/changelog_users
current index: 8822156503
It seems like we had about 4billion entries. We used this mainly for Robinhood and LMT.
I have some observations and questions as follows:
(a) I could not run the deregister command on both MDS and Robinhood server. Here is what happens on Robinhood server, even though file system is mounted.
# lctl --device scratch-MDT0000 changelog_deregister cl1
No device found for name scratch-MDT0000: Invalid argument
(b) Although I was able to run "lfs changelog_clear scratch-MDT0000 cl1 0" on Robinhood server.
Q1) Not sure why I was not able to run the "lctl --device scratch-MDT0000 changelog_deregister cl1" it complains with errors on MDS: "error: changelog_deregister: No such file or directory"
Q2)*** When we hit this issue, files that were in transaction/or being edited shows up as empty after I cleared changelog? Is this an expected behavior? Or something else is going on here?
Q3)*** It seems like every file in edit mode during this issue is showing up empty and complains about "Bad address" if we try to save it or remove it. I understood changelog is mainly for stats and profiling, data should not be affected if we clear changelogs, does it?.
Q4) We are setting up our new Lustre-ZFS solution in the next couple of weeks along with Robinhood and LMT, assuming we may run into this issue in the future, what would you recommend as far as setting up changelog? Is there a system variable that can be used to increase or decrease the amount of changelogs that could be stored?
Any help/insight here is greatly appreciated.