Anthony, So it sounds like I need to make a new crush rule for replicated pools that specifies default-hdd and the device class? (Or should I go the other way around? I think I'd rather change the replicated pools even though there's more of them.) Then, after I create this new rule, I simply assign the pool to a new crush rule using a command similar to the one shown in your note in the link you referenced? Thanks. -Dave -- Dave Hall Binghamton University kdhall@xxxxxxxxxxxxxx On Wed, Sep 18, 2024 at 2:10 PM Anthony D'Atri <anthony.datri@xxxxxxxxx> wrote: > > > > Helllo, > > I've reviewed some recent posts in this list and also searched Google for > info about autoscale and overlapping roots. In what I have found I do not > see anything that I can understand regarding how to fix the issue - > probably because I don't deal with Crush on a regular basis. > > > > Checkout the Note in this section: > https://docs.ceph.com/en/reef/rados/operations/placement-groups/#viewing-pg-scaling-recommendations > > I added that last year I think it was as a result of how Rook was creating > pools. > > > From what I read and looking at 'ceph osd crush rule dump', it looks like > the 8 replicated pools have > > "op": "take", > "item": -1, > "item_name": "default" > > whereas the 2 EC pools have > > "op": "take", > "item": -2, > "item_name": "default~hdd" > > To be sure, all of my OSDs are identical - HDD with SSD WAL/DB. > > Please advise on how to fix this. > > > The subtlety that's easy to miss is that when you specify a device class > for only *some* pools, the pools/rules that specify a device class > effectively act on a "shadow" CRUSH root. My terminology may be inexact > there. > > So I think if you adjust your CRUSH rules so that they all specify a > device class -- in your case all the same device class -- your problem (and > balancer performance perhaps) will improve. > > > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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