Re: BlueStore and maximum number of objects per PG

[Mike <mike.almateia@gmail.com>]

On Tue, 2017-02-21 at 21:04 +0100, Wido den Hollander wrote:
> Hi,
> 
> I'm about to start a test where I'll be putting a lot of objects into BlueStore and
> see how it holds.
> 
> The reasoning behind is that I have a customer which has 165M objects in it's cluster
> which results in some PGs having 900k objects.
> 
> For FileStore with XFS this is quite heavy. A simple scrub takes ages.
> 
> The problem is that we can't simply increase the number of PGs since that will
> overload the OSDs as well.

Also the problem stands if have a huge amount _small_ objects: capacity of hardware is
enough (20% used) but PG quantity isn't.
 
> 
> On the other hand we could add hardware, but that also takes time.
> 
> So just for the sake of testing I'm looking at trying to replicate this situation
> using BlueStore from master.
> 
> Is there anything I should take into account? I'll probably be just creating a lot
> (millions) of 100 byte objects in the cluster with just a few PGs.
> 
> Wido
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