Hi, thanks for your response. Clients are about 6, and 4 of them are the most of time on standby. Only two are active servers that are serving the webpage. Also we've a varnish on front, so are not getting all the load (below 30% in PHP is not much). About the MDS cache, now I've the mds_cache_memory_limit at 8Mb. I've tested also 512Mb, but the CPU usage is the same and the MDS RAM usage grows up to 15GB (on a 16Gb server it starts to swap and all fails). With 8Mb, at least the memory usage is stable on less than 6Gb (now is using about 1GB of RAM).
What catches my attention, is the huge difference between kernel and fuse. Why the kernel client is not notizable and the fuse client is using the most of CPU power... Greetings. 2018-07-23 14:01 GMT+02:00 Paul Emmerich <[email protected]>: > Hi, > > do you happen to have a relatively large number of clients and a > relatively small cache size on the MDS? > > > Paul > > 2018-07-23 13:16 GMT+02:00 Daniel Carrasco <[email protected]>: > >> Hello, >> >> I've created a Ceph cluster of 3 nodes (3 mons, 3 osd, 3 mgr and 3 mds >> with two active). This cluster is for mainly for server a webpage (small >> files) and is configured to have three copies of files (a copy on every >> OSD). >> My question is about ceph.fuse clients: I've noticed an insane CPU usage >> when the fuse client is used, while the kernel client usage is unnoticeable. >> >> For example, now i've that machines working with kernel client and the >> CPU usage is less than 30% (all used by php processes). When I change to >> ceph.fuse the CPU usage raise to more than 130% and even sometimes up to >> 190-200% (on a two cores machines means burn the CPU). >> >> Now I've seen two warnings on the cluster: >> 1 MDSs report oversized cache >> 4 clients failing to respond to cache pressure >> >> and I think that maybe is a lack of capabilities on ceph kernel modules, >> so I want to give a try to fuse module but I've the above problem. >> >> My SO is Ubuntu 16.04 x64 with kernel version 4.13.0-45-generic and ceph >> server/client version is 12.2.7. >> >> How I can debug why that CPU usage?. >> >> Thanks! >> -- >> _________________________________________ >> >> Daniel Carrasco Marín >> Ingeniería para la Innovación i2TIC, S.L. >> Tlf: +34 911 12 32 84 Ext: 223 >> www.i2tic.com >> _________________________________________ >> >> _______________________________________________ >> ceph-users mailing list >> [email protected] >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> > > > -- > Paul Emmerich > > Looking for help with your Ceph cluster? Contact us at https://croit.io > > croit GmbH > Freseniusstr. 31h > <https://maps.google.com/?q=Freseniusstr.+31h+81247+M%C3%BCnchen&entry=gmail&source=g> > 81247 München > <https://maps.google.com/?q=Freseniusstr.+31h+81247+M%C3%BCnchen&entry=gmail&source=g> > www.croit.io > Tel: +49 89 1896585 90 > -- _________________________________________ Daniel Carrasco Marín Ingeniería para la Innovación i2TIC, S.L. Tlf: +34 911 12 32 84 Ext: 223 www.i2tic.com _________________________________________
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