On Mon, 2006-07-17 at 21:43 -0400, seth vidal wrote: > On Tue, 2006-07-18 at 02:31 +0100, Andy Burns wrote: > > seth vidal wrote: > > > > > Where would you like to place the magical no-single-points-of-failure > > > router? > > > > :-) > > > > Use round-robin DNS for mirrors.fedoraproject.org resolving to > > geographically dispersed servers? > > and if one of the servers fail then 1 out every N dns requests fail to > find the host b/c the resolving host is down. > oh - but you say - have the dns tables get updated so if a host goes > down it gets taken out of the search? That's why dns caching (yes, > despite TTLs) sucks. > If the server has multiple DNS aliases and then the client can be written to fetch multiple aliases in a single DNS request and try several before giving up. The client could also cache a copy of the mirror list to fall back. I imagine the client could even try a couple of servers from the previous cached list before contacting the central server for a refresh (which could reduce the load on the server hosting the mirror list). The even better solution is to have multiple dispersed servers with the _same_ IP. This can be done for UDP using IP Anycast but isn't suited to TCP/HTTP traffic since sequential packets can get sent to different servers. http://www.net.cmu.edu/pres/anycast/ http://en.wikipedia.org/wiki/Anycast Jon -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
