RE: Mirroring/load-balance two servers
> www IN CNAME 12.34.56.78 > www IN CNAME 9.10.11.12 > www IN CNAME 65.4.3.21 Those should be 'A's. And you propably want a *short* livetime. > The DNS standard will give out a different address for every This is a particular feature of ICS (www.isc.org) their BIND named distribution; not part of any standard. You propably also want to look at Dynamic DNS update or Secure Dynamic DNS update in conjuction with snmp or some other actiev probing; as to mask out non responding addresses within a few time-to-live intervals. Typical propbing rates are livetime/2 sort of rates. Dw To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
RE: Mirroring/load-balance two servers
> > The only problem with using DNS round robin like this, is > that, in this scenario when 1 server is down, on average 1 in > 3 requests to the web server will fail. But as previous > posters have commented DNS should respond with the same 3 > addresses, but it will rotate the order each time, in the > version ( named 8.3.4-REL Sun Feb 9 01:23:18 GMT 2003 on > 4.7-STABLE of the same date ) I am using it appears to return > the addresses in some sort of random order at least it does > for me in my test. In reality, what happens to the user that connects to the offline server? Can he just refresh his browser and if he then gets one of the other IP addresses then the page will display fine? Jonas Fornander - System Administrator Netwood Communications, LLC - www.netwood.net Find out why we're better - 310-442-1530 To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
Re: Mirroring/load-balance two servers
Jonas Fornander wrote: Does anyone know if there is a "simple" way to mirror two servers without spending $ on hardware? I'm NOT talking about mirroring the OS and the files, I'm talking about sending http requests to a second server if the first server is down/un-reachable. This is sometimes referred to as load-balancing. The second server doesn't have to be updated in realtime, it just needs to have a fairly current version of the data files of the main server. So, for example if the main server goes off line for any reason, then web pages would be served up from the second server instead. Can this be accomplished with DNS? Jonas Fornander - System Administrator Netwood Communications, LLC - www.netwood.net Find out why we're better - 310-442-1530 Google for "round-robin DNS", that should get you started. -- R To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
Re: Mirroring/load-balance two servers
The only problem with using DNS round robin like this, is that, in this scenario when 1 server is down, on average 1 in 3 requests to the web server will fail. But as previous posters have commented DNS should respond with the same 3 addresses, but it will rotate the order each time, in the version ( named 8.3.4-REL Sun Feb 9 01:23:18 GMT 2003 on 4.7-STABLE of the same date ) I am using it appears to return the addresses in some sort of random order at least it does for me in my test. On Thu, 6 Mar 2003 12:09:06 -0800 "Aaron Burke" <[EMAIL PROTECTED]> wrote: > > "Aaron Burke" <[EMAIL PROTECTED]> writes: > > > > > To my knowlege, yes. Lets say you had a server called www. > > > You would just give it two addresses in your domain configuration > > > files. > > > > > > www IN CNAME 12.34.56.78 > > > www IN CNAME 9.10.11.12 > > > www IN CNAME 65.4.3.21 > > > > That should be A records, not CNAMEs. > Err, you are correct, my mistake. > > > > > > The DNS standard will give out a different address for every > > > query. To get the address 12.34.56.78 twice, you would have > > > to make 4 unique queries for the server records. > > > > Where does the standard say that? Most servers will return the > > records in the same order each time by default, and my reading of the > > standards is that this is perfectly acceptable behaviour. > > I have personally not read the standard. It is just information > thats been given to me by some knowlegable friends. > > > To Unsubscribe: send mail to [EMAIL PROTECTED] > with "unsubscribe freebsd-questions" in the body of the message > -- David Dooley [EMAIL PROTECTED] pgp0.pgp Description: PGP signature
RE: Mirroring/load-balance two servers
> "Aaron Burke" <[EMAIL PROTECTED]> writes: > > > To my knowlege, yes. Lets say you had a server called www. > > You would just give it two addresses in your domain configuration > > files. > > > > www IN CNAME 12.34.56.78 > > www IN CNAME 9.10.11.12 > > www IN CNAME 65.4.3.21 > > That should be A records, not CNAMEs. Err, you are correct, my mistake. > > > The DNS standard will give out a different address for every > > query. To get the address 12.34.56.78 twice, you would have > > to make 4 unique queries for the server records. > > Where does the standard say that? Most servers will return the > records in the same order each time by default, and my reading of the > standards is that this is perfectly acceptable behaviour. I have personally not read the standard. It is just information thats been given to me by some knowlegable friends. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
Re: Mirroring/load-balance two servers
"Aaron Burke" <[EMAIL PROTECTED]> writes: > To my knowlege, yes. Lets say you had a server called www. > You would just give it two addresses in your domain configuration > files. > > www IN CNAME 12.34.56.78 > www IN CNAME 9.10.11.12 > www IN CNAME 65.4.3.21 That should be A records, not CNAMEs. > The DNS standard will give out a different address for every > query. To get the address 12.34.56.78 twice, you would have > to make 4 unique queries for the server records. Where does the standard say that? Most servers will return the records in the same order each time by default, and my reading of the standards is that this is perfectly acceptable behaviour. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
RE: Mirroring/load-balance two servers
> Does anyone know if there is a "simple" way to mirror two servers > without spending $ on hardware? I'm NOT talking about mirroring the > OS and the files, I'm talking about sending http requests to a second > server if the first server is down/un-reachable. This is sometimes > referred to as load-balancing. > > The second server doesn't have to be updated in realtime, it just needs > to have a fairly current version of the data files of the main server. > So, for example if the main server goes off line for any reason, then > web pages would be served up from the second server instead. > > Can this be accomplished with DNS? To my knowlege, yes. Lets say you had a server called www. You would just give it two addresses in your domain configuration files. www IN CNAME 12.34.56.78 www IN CNAME 9.10.11.12 www IN CNAME 65.4.3.21 The DNS standard will give out a different address for every query. To get the address 12.34.56.78 twice, you would have to make 4 unique queries for the server records. One good example of this is to look at www.yahoo.com in nslookup. Default Server: localhost.jupiter.sol Address: 127.0.0.1 > www.yahoo.com Server: localhost.jupiter.sol Address: 127.0.0.1 Non-authoritative answer: Name:www.yahoo.akadns.net Addresses: 216.109.125.73, 216.109.125.70, 64.58.76.223, 216.109.125.72 216.109.125.67, 216.109.125.65, 216.109.125.66, 64.58.76.227, 64.58.76.228 216.109.125.71, 64.58.76.230, 216.109.125.69, 64.58.76.225 Aliases: www.yahoo.com > > Jonas Fornander - System Administrator > Netwood Communications, LLC - www.netwood.net > Find out why we're better - 310-442-1530 > > > To Unsubscribe: send mail to [EMAIL PROTECTED] > with "unsubscribe freebsd-questions" in the body of the message > > To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
Mirroring/load-balance two servers
Does anyone know if there is a "simple" way to mirror two servers without spending $ on hardware? I'm NOT talking about mirroring the OS and the files, I'm talking about sending http requests to a second server if the first server is down/un-reachable. This is sometimes referred to as load-balancing. The second server doesn't have to be updated in realtime, it just needs to have a fairly current version of the data files of the main server. So, for example if the main server goes off line for any reason, then web pages would be served up from the second server instead. Can this be accomplished with DNS? Jonas Fornander - System Administrator Netwood Communications, LLC - www.netwood.net Find out why we're better - 310-442-1530 To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
