Hi, it's been a while since im using Ceph, and still im a little ashamed that when certain situation happens, i dont have the knowledge to explain or plan things. Basically what i dont know is, and i will do an exercise. EXCERCISE: a virtual machine running on KVM has an extra block device where the datafiles of a database runs (this block device is exposed to the vm using libvirt) facts. * the db writes to disk in 8K blocks * the connection between the phisical compute node and Ceph has an MTU of 1500 * the QEMU RBD driver uses a stipe unit of 2048 kB and a stripe count of 4. * everything else is default So conceptually, if someone can explain me, what happens from the momment the DB contained on the VM commits to disk a query of 20MBytes, what happens on the compute node, what happens on the client's file striping, what happens on the network (regarding packages, if other than creating 1500 bytes packages), what happens with rados objects, block sizes, etc. I would love to read this from the bests, mainly because as i said i dont understand all the workflow of blocks, objects, etc. thanks to everyone ! -- Alejandrito _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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