Hello, On Wed, 22 Feb 2017 15:07:48 +0800 (HKT) Horace wrote:
> Dear all, > > Is anybody got any experience on this product? It is a BBU backed NVRAM > cache, I think it is most fit on Ceph. > > https://www.microsemi.com/products/storage/flashtec-nvram-drives/nv1616 > Not this product, but some people here on this ML looked at similar things in the past. And while fast and won't wear out, it's hard to find a good (economical) use case for these. 1. For HDD backed OSDs this kind of NVRAM unit is overkill and at 16GB also something that may prove too small with more than 8 HDDs. 2. For SSD backed OSDs it's a much better fit, however can you afford both and more importantly do you need that performance and can actually realize it? Your CPUs are going to become bottlenecks at some point. 3. For NVMe backed OSDs it would be a good fit, too. But given the PCIe lanes needed you may wind up only with 4 OSDs per node. Also the fastest CPUs you can find (high speed, not cores). And the price tag of this combo is going to be something for specialist use and/or really well funded operations. Lastly while BlueStore will of course also profit from some of its data on fast storage (WAL, DB) the exact size requirements are not exactly clear to me at this time. What it definitely won't need are (relatively large) journals. Christian -- Christian Balzer Network/Systems Engineer ch...@gol.com Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
