On Aug 11, 2005, at 13:07, Bobby Ölander wrote:
I'm working at a company called Com Hem AB in Sweden, we are at the moment the biggest cabelnetwork company in Sweden.
I have a question that concerns the hardware in the server that should be a primary DNS (even the hardware on the secondary DNS could be nice to know about).
What I wonder most about is, should the primary DNS be build with a RAID-system? Or is that not importent of the fact there is a secondary DNS?
Bobby, it is not possible to answer your questions in detail. It's not clear what your company's requirements are or what sort of DNS service is needed: number of queries, authoritative or caching (or both!) name servers, frequency of zone file & configuration file changes, number of zones & RRs to serve, SLAs, peak and steady-state throughput, etc, etc. Without this information, all you can expect here is educated guesswork. Perhaps someone on the WG could work with you to document your requirements and devise a suitable DNS infrastructure. After that comes the hardware specification... Unless you will be managing huge datasets -- eg hundreds of thousands of zones and/or millions of resource records -- a RAID solution would be overkiil. For DNS, the most significant advantage of RAID would be the facility to hot-swap broken disk drives. That would reduce the window where customers couldn't update their zone files. Most name servers store everything in RAM and will generally only load zone files from disk when they start. So having the DNS data "backed up" by a RAID system is unlikely to be worth it. Unless of course fixing a broken drive and restoring from backup takes so long that it annoys your customers . Or embarrasses your management. The DNS is designed to be resilient and can cope with server outages. So if one of the name servers for a zone dies, the others will seamlessly pick up the load. The only exception concerns the zone's master (primary) server. This is the *only* place where the contents of a zone can be changed. So if the master server dies, the zone can't be updated until it returns. The other servers for the zone will of course continue to answer queries for that zone. They'll automatically resynchronise with the master once it's back on-line too. Memory provision is usually more important for a name server than the CPU or disk subsystem because name servers almost always store everything in RAM. The amount of RAM depends on the number of zones and resource records the name server loads. [A good rule of thumb for BIND is allow 1K of RAM for each zone and 100 bytes for each RR.] The number of queries the server gets can also be a factor. Big Iron is rarely if ever justified for DNS. Commodity hardware is often used though some people prefer low-end Sun/IBM/HP boxes because they neatly fill a 1U or 2U slot in a 19" rack.