2012/10/31 Stefan Kleijkers <stefan@xxxxxxxxxxxx>: > As far as I know, this is correct. You get a ACK (on the write) back after > it landed on ALL three journals (or/and osds in case of BTRFS in parallel > mode). So If you lose one node, you still have it in two more nodes and they > will commit it to disk. After recovering the missing node/osd it will get > the data from one of the other nodes. So you won't lose any data. In this case I can suppose that ceph writing speed is relative to the journal's writing speed and never to ODS disks. Let's assume a journal size of 150GB, capable to write at 200MB/s in a 2gbit/s network (lacp between two gigabit ports), no replica between OSDs and very very slow SATA disk (5400 RPM, for example, much slower than jurnal). Just a single osd. Ceph will write at 200MB/s, and in background it will flush journals to disk, right? I can assume that journal is a buffer and RBD will write only to it. -- 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
