[LU-1628] du for a certain set of user seems to take an inordinate amount of time to complete

• Type: Story
• Resolution: Unresolved
• Priority: Minor
• Environment: lustre 1.8.5
• Assignee: Oleg Drokin
• Reporter: Joe Mervini

Description

This is just a question of observance:

We recently ran into a problem with mballoc that was causing OSTs to misbehave. We considered that the capacity/usage of the file system was the culprit (which ultimately appear to be the case - since we got down below 92% everything was happy) and as a result I started a process of examining every user's usage with du. Beyond the fact that large files are reported better than small files I am running into a situation where the last 1% of the user's are taking an extraordinary amount of time to complete a du - on the order of 2 or more days.

At first I thought that the problem was the number of files associated with the users directory (and in fact the users that remain have > 5M files in their directories) but other users have similar number of files yet their du output completes in hours. (Caveat: I haven't checked the stripe sizes on the directories of the users that are still running.)

So my question is: has this behavior been observed in other systems and what are the conclusions.

This is not high priority. Just a matter of curiosity.