[PVE-User] Ceph Cache Tiering

Kautz, Valentin valentin.kautz at iosb.fraunhofer.de
Mon Oct 10 10:36:44 CEST 2016

I can only acknowledge this. Speed went down as the cache tier went full. Even with superfast PCIe SSDs.

Additionally i think it is error prone.
I ran into the problem, that a ssd stuck because it was full causing the complete storage to stuck.
There is a parameter for the maximum size of the cache, but it does not prevent a single ssd in the cache-tier to be filled completely - at least i didn't find any method despite of the balance factor for the osds, but that didn't help.
I my setup there were 3 SSDs for caching.
One of them went full, even when the sum of the used storage was smaller than the maximum cache size.

Kind Regards

Von: pve-user [pve-user-bounces at pve.proxmox.com]" im Auftrag von "Lindsay Mathieson [lindsay.mathieson at gmail.com]
Gesendet: Sonntag, 9. Oktober 2016 00:21
An: PVE User List
Betreff: Re: [PVE-User] Ceph Cache Tiering

On 9/10/2016 7:45 AM, Lindsay Mathieson wrote:
> cache tiering was limited and a poor fit for VM Hosting, generally the
> performance was with it

"was *worse* with it"


Lindsay Mathieson

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