Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Saturday 18 October 2008 00:10:13 Stefan Seifert wrote: > On Friday, 17. October 2008, Little, Kevin wrote: > > I searched the archives for this, but found nothing. > > > > I've seen mentioned > > (http://fghaas.wordpress.com/2007/06/26/when-not-to-use-drbd/) that the > > fail-over time for DRBD+Heartbeat is on the order of 20 seconds. > > > > First, is this accurate? > > The number highly depends on your setup and the applications you're > running. As such it cannot be accurate. What it does show is the order of > magnitude you can expect. Depending on your setup it can also be two > seconds or even a minute. > > > Second, what portion of the 20 seconds is a > > function of Heartbeat, what portion is a function of DRBD? > > DRBD itself depends just on your ping-int and ping-timeout and maybe the > timeout value. You can tune them to your system and can even get down to > about one second of fail over time. But don't overdo it. If your system is > just under very high stress and answers late, you may push it to a fail > over at a time, where it's not needed and possibly the worst timing. Be > sensible. > > In my experience most of the time is not used for detecting the fail over > condition, but simply for starting services on the stand by node. This > could be minimized if the applications can cope with getting their data > files at runtime and thus can be started at system boot. > > Regards, > Stefan Also you have to understand that this article is written mainly for active/passive setups. In active/active setups(if your application can handle this setup) the failover time is far less. Regards Marian Marinov