I will read your cache thread, thnx. Now we have the following setup in mind: X10SRH-CLN4F E5-2620v4 32GB/64GB RAM 6x 2TB (start with 4 drives) 1x S3710 200GB for Journaling In the future adding 2 SSD's for caching, or is it an option to use a P3700 400GB (or two) for journaling and caching ?
Kind regards, Tom On Mon, Aug 1, 2016 at 2:46 PM, Christian Balzer <[email protected]> wrote: > > Hello, > > On Mon, 1 Aug 2016 14:34:43 +0200 Tom T wrote: > > > Hi Christian, > > > > Thnx for your reply. > > > > Case: > > CSE-825TQC-600LPB > > > > I made a typo with the CPU, it's a E3-1240 v5 3.5Ghz. > > So a E5-2620 v4 is recommended when i want to add SSD for caching ? > > > It's more a question of core count (and speed per core), an E5-1650 v3 for > example would do the trick (in all situations) with 4 HDD OSDs with SSD > journal and 1-2 SSD OSDs. > > > With a caching tier, is the data on the caching tier a copy from data on > > the normal tier ? > You want to re-read the respective documentation and the various threads > on this ML about cache tiering, including my > "Cache tier operation clarifications" one. > > In a reasonably busy cluster a cache pool will be very different from the > base pool and some hot data may never reach the base pool, ever. > > Meaning that your cache pool needs to be just as reliable as everything > else. > > > Is a caching tier with one SSD recommended or should i always have two > SSD > > in replicated mode ? > > > See above. > > Christian > > > > Kind regards, > > Tom > > > > > > > > On Mon, Aug 1, 2016 at 2:00 PM, Christian Balzer <[email protected]> wrote: > > > > > > > > Hello, > > > > > > On Mon, 1 Aug 2016 11:09:00 +0200 Tom T wrote: > > > > > > > Hi Ceph users > > > > > > > > We are planning to setup a small ceph cluster, starting with 3 nodes > for > > > > VM's. > > > > I have some question about CPU and caching > > > > > > > > We would like to start with the following config: > > > > > > > > > > > > Supermicro X11SSI-LN4F > > > In which case? > > > > > > > Intel E3-1246 v3 3.5Ghz > > > A bit dated, but fast enough. > > > > > > > 32GB RAM > > > While enough for 4 OSDs, don't skimp on RAM if you can afford, reads > will > > > thank you for it. > > > > > > > S3500 80GB M.2 for OS > > > If you're short on money, maybe use a 535 (or 2!) for that purpose. > > > > > > > AOC-S3008L-L8e (LSI SAS3008) > > > > 4x 2TB ST2000NM0034 SAS12Gb > > > > > > I fail to see the need/point for 7.2k RPM HDDs with a mere 128MB of > cache > > > hanging of a 12Gb/s bus, but maybe that's just me. > > > > > > > 1x Intel 200GB S3710 for journal (via onboard SATA) > > > Good enough. > > > > > > > 4x 1Gb for networking > > > > > > > Unless all your clients also are limited to GbE and you have no budget > to > > > change that, don't. > > > > > > For VM's latency will be one of your biggest nemesis (nemesii?), use > > > faster (lower latency) networking. > > > > > > > Questions: > > > > Is the CPU enough ? > > > See above. > > > > > > > I would like to run the monitoring deamon on the same host, would > this > > > be a > > > > problem ? > > > > > > > Just within the normal usage needs, more RAM in that case anyway. > > > > > > > Optionally i would like to add an extra SSD for caching > > > Not really recommended with that server and not particular helpful with > > > that network. > > > A single SSD of any caliber will/can eat one of your CPU cores by > itself > > > and then ask for seconds. > > > > > > > Does write-back caching also optimize the reads ? > > > Yes, subject to "correct" configuration of course. > > > > > > > Do I need two SSD's per node > > > > > > > From a performance point of view, not so much. > > > Your network can't even saturate one 200GB DC S3710. > > > > > > From a redundancy point of view you might be better off with more > nodes. > > > > > > Christian > > > > > > > > > > > Kind regards, > > > > Tom > > > > > > > > > -- > > > Christian Balzer Network/Systems Engineer > > > [email protected] Global OnLine Japan/Rakuten Communications > > > http://www.gol.com/ > > > > > > -- > Christian Balzer Network/Systems Engineer > [email protected] Global OnLine Japan/Rakuten Communications > http://www.gol.com/ >
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