Thanks. -- Regards Dominik 2013/11/26 Sage Weil <sage@xxxxxxxxxxx>: > On Tue, 26 Nov 2013, Christoph Hellwig wrote: >> On Tue, Nov 26, 2013 at 11:43:07AM +0100, Dominik Mostowiec wrote: >> > Hi, >> > I found in doc: http://ceph.com/docs/master/start/os-recommendations/ >> > "Putting multiple ceph-osd daemons using XFS or ext4 on the same host >> > will not perform as well as they could." >> > >> > For now recommended filesystem is XFS. >> > This means that for the best performance setup should be 1 OSD per host? >> >> Btw, could anyone clarify where that stance comes from, that is numbers >> to back it up. > > If syncfs(2) is not present, we have to use sync(2). That means you have > N daemons calling sync(2) to force a commit on a single fs, but all other > mounted fs's are also synced... which means N times the sync(2) calls. > > Fortunately syncfs(2) has been around for a while now, so this only > affects really old distros. And even when glibc does not have a syscall > wrapper for it, we try to call the syscall directly. > > sage -- Pozdrawiam Dominik -- 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
