[ceph-users] Re: Erasure coded pool chunk count k

2021-10-05 Thread Christian Wuerdig
A couple of notes to this: Ideally you should have at least 2 more failure domains than your base resilience (K+M for EC or size=N for replicated) - reasoning: Maintenance needs to be performed so chances are every now and then you take a host down for a few hours or possibly days to do some

[ceph-users] Re: Erasure coded pool chunk count k

2021-10-04 Thread Anthony D'Atri
The larger the value of K relative to M, the more efficient the raw :: usable ratio ends up. There are tradeoffs and caveats. Here are some of my thoughts; if I’m off-base here, I welcome enlightenment. When possible, it’s ideal to have at least K+M failure domains — often racks,

[ceph-users] Re: Erasure coded pool chunk count k

2021-10-04 Thread Etienne Menguy
Hi, It depends of hardware, failure domain, use case, overhead. I don’t see an easy way to chose k and m values. - Etienne Menguy etienne.men...@croit.io > On 4 Oct 2021, at 16:57, Golasowski Martin wrote: > > Hello guys, > how does one estimate number of chunks for erasure coded pool ( k =