hi, you can find the ceph architecture on this page: http://ceph.com/docs/master/architecture/ the interessting picture for you may be this one: http://ceph.com/docs/master/_images/ditaa-54719cc959473e68a317f6578f9a2f0f3a8345ee.png your client writes the file to one osd, and before this osd acknowledges your write request, it ensure that it is copied to other osd(s). Mit freundlichen Grüßen / Best Regards, -- Uwe Grohnwaldt ----- Original Message ----- > From: "Cristian Falcas" <cristi.falcas@xxxxxxxxx> > To: "Wido den Hollander" <wido@xxxxxxxx> > Cc: ceph-users@xxxxxxxxxxxxxx > Sent: Samstag, 7. Dezember 2013 15:44:08 > Subject: Re: how to set up disks in the same host > > Hi, > > Thank you for the answer. > > But how fast is the replication from ceph happening? Because if it's > not almost instantaneously you will loose some data is the hard drive > fails. > > Does anybody know how fast are the copies written on other OSDs? > > > > On Fri, Dec 6, 2013 at 12:31 PM, Wido den Hollander <wido@xxxxxxxx> > wrote: > > On 12/06/2013 11:00 AM, Cristian Falcas wrote: > >> > >> Hi all, > >> > >> What will be the fastest disks setup between those 2: > >> - 1 OSD build from 6 disks in raid 10 and one ssd for journal > >> - 3 OSDs, each with 2 disks in raid 1 and a common ssd for all > >> journals (or more ssds if ssd performance will be an issue) > >> > >> Mainly, will 1 OSD raid 10 be faster or slower then independent > >> OSDs? > >> > > > > Simply run 6 OSDs without any RAID and one SSD for the journaling. > > > > Danger is though, if you loose the journal, you loose all OSDs. So > > better > > place two SSDs and then 3 OSDs per journal and make sure that using > > crush > > objects go two OSDs on the different journals. > > > > You shouldn't use RAID underneath a OSD, let the replication handle > > all > > that. > > > >> Best regards, > >> Cristian Falcas > >> _______________________________________________ > >> ceph-users mailing list > >> ceph-users@xxxxxxxxxxxxxx > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >> > > > > > > -- > > Wido den Hollander > > 42on B.V. > > > > Phone: +31 (0)20 700 9902 > > Skype: contact42on > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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