Am 20.01.16 um 11:30 schrieb Christian Balzer: > > Hello, > > On Wed, 20 Jan 2016 10:01:19 +0100 Götz Reinicke - IT Koordinator wrote: > >> Hi folks, >> >> we plan to use more ssd OSDs in our first cluster layout instead of SAS >> osds. (more IO is needed than space) >> >> short question: What would influence the performance more? more Cores or >> more GHz/Core. >> >> Or is it as always: Depeds on the total of >> OSDs/nodes/repl-level/etc ... :) >> > > While there certainly is a "depends" in there, my feeling is that faster > cores are more helpful than many, slower ones. > And this is how I spec'ed my first SSD nodes, 1 fast core (Intel, thus 2 > pseudo-cores) per OSD. > The reasoning is simple, an individual OSD thread will run (hopefully) on > one core and thus be faster, with less latency(!). > >> If needed, I can give some more detailed information on the layout. >> > Might be interesting for other sanity checks, if you don't mind. With pleasure. The basic setup was: 6*24 SATA Nodes, simple "replication" (size = 2), two datacenters, 20Gbit bonded LAN. We calculated with 2x Intel Xeon E5-2630v3 8-Core 2,4GHz per OSD Node = 32 vCPUs each. (hypertreaded) On the other hand, if we talk about one core per osd two E5-2620v3 6-Core would do per node. But regarding the total cost we are faced with (upgrading network, more fibers etc) ... the cost for the more cores do not hurt. And having some cores "as spare" sounded good as we would install the mons on the OSD node for now. Later we discussed the design with an external consultant and added the new and "OMG I forgot to tell you that we need" requirements and ended up with: three pool storage classes: fast and big more small IO, fast and not so big (VM images) and cachetiered ec-pool biiiig videofiles. Using the 6-Node 2 datacenter layout we ended up with a nice OSD spreading and layout which sounds good to me. The most important "new" thing was: using SSD for the pools, not just for journal and OS. So I ended up with the question, if the CPUs would have any good or bad influence in that new SSDish-design. Thanks for all the feedback and thoughts/comments so far. CONCLUSION so far: From my POV the 2630v3 is good for us. Cheers . Götz -- Götz Reinicke IT-Koordinator Tel. +49 7141 969 82420 E-Mail goetz.reinicke@xxxxxxxxxxxxxxx Filmakademie Baden-Württemberg GmbH Akademiehof 10 71638 Ludwigsburg www.filmakademie.de Eintragung Amtsgericht Stuttgart HRB 205016 Vorsitzender des Aufsichtsrats: Jürgen Walter MdL Staatssekretär im Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg Geschäftsführer: Prof. Thomas Schadt
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