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      1 .. Copyright (C) Internet Systems Consortium, Inc. ("ISC")
      2 ..
      3 .. SPDX-License-Identifier: MPL-2.0
      4 ..
      5 .. This Source Code Form is subject to the terms of the Mozilla Public
      6 .. License, v. 2.0.  If a copy of the MPL was not distributed with this
      7 .. file, you can obtain one at https://mozilla.org/MPL/2.0/.
      8 ..
      9 .. See the COPYRIGHT file distributed with this work for additional
     10 .. information regarding copyright ownership.
     11 
     12 .. _requirements:
     13 
     14 Resource Requirements
     15 =====================
     16 
     17 .. _hw_req:
     18 
     19 Hardware Requirements
     20 ---------------------
     21 
     22 DNS hardware requirements have traditionally been quite modest. For many
     23 installations, servers that have been retired from active duty
     24 have performed admirably as DNS servers.
     25 
     26 However, the DNSSEC features of BIND 9 may be quite CPU-intensive,
     27 so organizations that make heavy use of these features may wish
     28 to consider larger systems for these applications. BIND 9 is fully
     29 multithreaded, allowing full utilization of multiprocessor systems for
     30 installations that need it.
     31 
     32 .. _cpu_req:
     33 
     34 CPU Requirements
     35 ----------------
     36 
     37 CPU requirements for BIND 9 range from i386-class machines, for serving
     38 static zones without caching, to enterprise-class machines
     39 to process many dynamic updates and DNSSEC-signed zones, serving
     40 many thousands of queries per second.
     41 
     42 .. _mem_req:
     43 
     44 Memory Requirements
     45 -------------------
     46 
     47 Server memory must be sufficient to hold both the cache and the
     48 zones loaded from disk. The :any:`max-cache-size` option can
     49 limit the amount of memory used by the cache, at the expense of reducing
     50 cache hit rates and causing more DNS traffic. It is still good practice
     51 to have enough memory to load all zone and cache data into memory;
     52 unfortunately, the best way to determine this for a given installation
     53 is to watch the name server in operation. After a few weeks, the server
     54 process should reach a relatively stable size where entries are expiring
     55 from the cache as fast as they are being inserted.
     56 
     57 .. _intensive_env:
     58 
     59 Name Server-Intensive Environment Issues
     60 ----------------------------------------
     61 
     62 For name server-intensive environments, there are two
     63 configurations that may be used. The first is one where clients and any
     64 second-level internal name servers query the main name server, which has
     65 enough memory to build a large cache; this approach minimizes the
     66 bandwidth used by external name lookups. The second alternative is to
     67 set up second-level internal name servers to make queries independently.
     68 In this configuration, none of the individual machines need to have as
     69 much memory or CPU power as in the first alternative, but this has the
     70 disadvantage of making many more external queries, as none of the name
     71 servers share their cached data.
     72 
     73