Hello Filippos, On Wed, 4 Jun 2014 17:22:35 +0300 Filippos Giannakos wrote: > Hello Ian, > > Thanks for your interest. > > On Mon, Jun 02, 2014 at 06:37:48PM -0400, Ian Colle wrote: > > Thanks, Filippos! Very interesting reading. > > > > Are you comfortable enough yet to remove the RAID-1 from your > > architecture and get all that space back? > > Actually, we are not ready to do that yet. There are three major things > to consider. > > First, to be able to get rid of the RAID-1 setup, we need to increase the > replication level to at least 3x. So the space gain is not that great to > begin with. > > Second, this operation can take about a month for our scale according to > our calculations and previous experience. During this period of > increased I/O we might get peaks of performance degradation. Plus, we > currently do not have the necessary hardware available to increase the > replication level before we get rid of the RAID setup. > > Third, we have a few disk failures per month. The RAID-1 setup has > allowed us to seamlessly replace them without any hiccup or even a clue > to the end user that something went wrong. Surely we can rely on RADOS > to avoid any data loss, but if we currently rely on RADOS for recovery > there might be some (minor) performance degradation, especially for the > VM I/O traffic. > That. And in addition you probably never had to do all that song and dance of removing a failed OSD and bringing up a replacement. ^o^ One of the reasons I choose RAIDs as OSDs, especially since the Ceph cluster in question is not local. Christian -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Fusion Communications http://www.gol.com/ -- 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
