On Fri, 16 Dec 2016, Igor Fedotov wrote: > Hey All! > > Recently I realized that I'm unable to fit all my onodes ( 32768 objects/4Mb > each/4K alloc unit/no csum) in 15G RAM cache. > > Hence decided to estimate Onode in-memory size. > > At first I filled 4Mb object with a single 4M write - mempools indicate ~5K > mem usage for total onode metadata. Good enough. > > Secondly I refill that object with 4K writes. Resulting memusage = 574K!!! > Onode itself 704 bytes in 1 object. And 4120 other metadata items occupies > all other space. > > Then I removed SharedBlob from mempools. Resulting mem usage = 355K. The same > Onode size. And 3096 other metadata objects. Hence we had 1024 SharedBlob > instances thata took ~ 220K. > > > And finally I removed Blob instances from measurements. Resulting mem usage = > 99K. And 2072 other objects. Hence Blob instances take another ~250K Yikes! BTW you can get a full breakdown by type with 'mempool debug = true' in ceph.conf (-o 'mempool debug = true' on vstart.sh command line) without having to recompile. Do you mind repeating the test and including the full breakdown? > Yeah, that's the worst case( actually csum enable will give even more mem use) > but shouldn't we revisit some Onode internals due to such numbers? Yep! sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
