Dear Thomas, Indeed the stats show 1 single active thread, but as this display is lockless for performance reasons, the current operations may be moving while the stats are displayed, and thus give a false view of what's really going on. Do all other stat dumps look the same?
Otherwise, I'm concerned about the 10.08ms for "GET_INFO_FS" (basically stat()+getstripe()). It's quite a high latency (if operations were sequential, it would only make 100 stat per sec...). I wonder if having too much threads querying the lustre client might not be counterproductive. There is a way to fine tune the number of threads allowed by pipeline stage, to have a high parallelism on some operations (e.g. DB) while restricting the number of simultaneous calls to the FS. Regards, Thomas -----Message d'origine----- De : Thomas Roth <[email protected]> Envoyé : lundi 2 février 2026 21:58 À : '[email protected]' <[email protected]> Objet : [robinhood-support] idle threads Hi all, I have Robinhood v3.2 running on a Lustre 2.15, and might have misconfigured / misunderstood the thread count. The Robinhood box has 96 cores, so I have set the number of threads to 96 (EntryProcessor {nb_threads = 96;}) When checking the robinhood.log, most cores do nothing: 2026/02/02 21:46:58 [4479/1] STATS | ==== EntryProcessor Pipeline Stats === 2026/02/02 21:46:58 [4479/1] STATS | Idle threads: 95 2026/02/02 21:46:58 [4479/1] STATS | Id constraints count: 100 (hash min=0/max=3/avg=0.0) 2026/02/02 21:46:58 [4479/1] STATS | Name constraints count: 98 (hash min=0/max=2/avg=0.0) 2026/02/02 21:46:58 [4479/1] STATS | Stage | Wait | Curr | Done | Total | ms/op | 2026/02/02 21:46:58 [4479/1] STATS | 0: GET_FID | 0 | 0 | 0 | 0 | 0.00 | 2026/02/02 21:46:58 [4479/1] STATS | 1: GET_INFO_DB | 57 | 0 | 41 | 38819 | 0.35 | 2026/02/02 21:46:58 [4479/1] STATS | 2: GET_INFO_FS | 0 | 0 | 0 | 26390 | 10.08 | 2026/02/02 21:46:58 [4479/1] STATS | 3: PRE_APPLY | 0 | 0 | 0 | 37960 | 0.00 | 2026/02/02 21:46:58 [4479/1] STATS | 4: DB_APPLY | 1 | 1 | 0 | 37958 | 1.17 | 2.64% batched (avg batch size: 3.8) 2026/02/02 21:46:58 [4479/1] STATS | 5: CHGLOG_CLR | 0 | 0 | 0 | 38823 | 0.01 | 2026/02/02 21:46:58 [4479/1] STATS | 6: RM_OLD_ENTRIES | 0 | 0 | 0 | 0 | 0.00 | This is quite single-threaded ;-( Right now, the file system is not in production and quite idle, so Robinhood is working to close a gap of ~100M changelog entries. But I am afraid that with this configuration, once in production, the changelogs will run away and fill up the MDS disk. Regards, Thomas -- -------------------------------------------------------------------- Thomas Roth Department: IT Location: SB3 2.291 Phone: +49-6159-71 1453 Fax: +49-6159-71 2986 GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de Commercial Register / Handelsregister: Amtsgericht Darmstadt, HRB 1528 Managing Directors / Geschäftsführung: Prof. Dr. Thomas Nilsson, Dr. Katharina Stummeyer, Jörg Blaurock Chairman of the Supervisory Board / Vorsitzende des GSI-Aufsichtsrats: State Secretary / Ministerialrätin Dr. Andrea Fischer _______________________________________________ robinhood-support mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/robinhood-support _______________________________________________ robinhood-support mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/robinhood-support
