I have started playing around with Lustre changelogs, and I have noticed a behavior with the “lctl changelog_deregister” command that I don’t understand. I tried running a little test by enabling changelogs on my MDS server:
[root@server ~]# lctl --device orhydra-MDT0000 changelog_register orhydra-MDT0000: Registered changelog userid ‘cl5' On a client system, I ran “lfs changelog” to look at some of the entries. In particular, I was looking at the last entry index number to see how quickly entries were being added: [root@client ~]# lfs changelog orhydra-MDT0000 | tail -1 432339 11CLOSE 22:18:01.882533366 2018.01.26 0x3 t=[0x20000b4a7:0xe8de:0x0] …waited a bit... [root@client ~]# lfs changelog orhydra-MDT0000 | tail -1 694305 08RENME 22:24:39.345273014 2018.01.26 0x1 t=[0x20000b4d2:0x16f3d:0x0] p=[0x20000b528:0xe56a:0x0] restart.xml s=[0x20000b4d2:0x16f45:0x0] sp=[0x20000b528:0xe56a:0x0] restart.xml.tmp At this point, I didn’t have any changelog consumer in place. I was just simply looking at the entries. When I was done, I deregistered the changelog userid: [root@server ~]# lctl --device orhydra-MDT0000 changelog_deregister cl5 orhydra-MDT0000: Deregistered changelog user 'cl5' Based on what I read in the manual, this should remove all the changelog entries. However, when I checked, I found that there were still several thousand entries: [root@client ~]# lfs changelog orhydra-MDT0000 | head -1 705647 11CLOSE 22:24:57.281171001 2018.01.26 0x3 t=[0x20000ac25:0x1e308:0x0] [root@client ~]# lfs changelog orhydra-MDT0000 | tail -1 742926 11CLOSE 22:26:04.108790913 2018.01.26 0x3 t=[0x20000ac25:0x1e313:0x0] I tried to clear them using the lfs changelog_clear command, but of course that failed because the userid was no longer registered. I also waited a while in case it just took some time to clear the entries, but after several hours, they were still there. Am I misunderstanding what is supposed to happen when a userid is deregistered? Or did I mess up a command somewhere? Or is this a bug? -- Rick Mohr Senior HPC System Administrator National Institute for Computational Sciences http://www.nics.tennessee.edu _______________________________________________ lustre-discuss mailing list lustre-discuss@lists.lustre.org http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
