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CDM 06-MAR-2024 » History » Revision 11

Revision 10 (Brad Hubbard, 03/07/2024 02:58 AM) → Revision 11/12 (Brad Hubbard, 03/07/2024 04:42 AM)

h1. CDM 06-MAR-2024 

 - [Brad] Initial discussions around protecting the manager -> mon queue from overload by rogue modules 
 * Get a better understanding of what this throttle ("throttle-mgr_mon_messsages") represents (and why it seems to have any relation to the volume plugin) 
 * Try a test where the volumes plugin is artificially *hung* 
 ** Fail the fs (cephfs fail [fsname]), spawn a bunch of clients that send messages to the volumes plugin and see if we see this scenario happening. Something like `ceph fs subvolume create <fs_name> subvol.XYZ`. 
 * Etherpad to coordinate the response: [[https://pad.ceph.com/p/throttle-mgr_mon_messsages_engages_heavily]] 


 - [Patrick/Venky; if we're available] ceph-mgr throttles hit after module (volumes) finisher thread queue fills up with commands. This causes messenger threads to throttle commands/queries from other clients. Idea for discussion: throttle clients by connection to ensure fairness. 
 * Allocate each client a number of slots in the throttle and use this to ensure some level of fairness in servicing each module 
 * Note that we may have a far better understanding of how to resolve this once we have a far better understanding of the issue described in item 1 which is hitherto not really comprehensively understood.