DHCP + mysql
Randy Grimshaw
rgrimsha at syr.edu
Mon Mar 19 12:47:25 UTC 2007
What if a local, embedded SQL datastore was used? These have much higher
performance
and might easily replace OMAPI. Less certain but worthy of
consideration is background replication.
<><Randy
<><Randall Grimshaw
Room 203 Machinery Hall
Syracuse University
Syracuse, NY 13244
315-443-5779
rgrimsha at syr.edu
>>>> dhcp1 at thehobsons.co.uk 3/19/2007 3:29:07 AM >>>
>jgomez at infoweapons.com wrote:
>
>>Is it possible to use mysql or any database applications instead of
>>dhcpd.leases in keeping a persistent database of leases that has
assigned
>>to clients.?
>
>Technically, yes; in practice, no.
>
>AFAIK the ISC server does not have the capability to do this, and I
>seriously doubt that they would be interested in adding it. There are
>two main reasons :
>
>1) Performance.
>
>Appending to a log file is a fast operation, which means you can
>service clients quickly. Updating an SQL database is going to be VERY
>much slower and that would impinge on the ability of the server to
>service client requests in a timely manner. The current server is, I
>believe, single threaded - so if you introduce even a small delay
>into each transaction then you severely restrict the volume of
>transactions you can handle. Internally the ISC server keeps the data
>in hashed lists for quick searching, no SQL database is going to
>match that for query speed.
>
>2) Security
>
>It is a requirement of the rfc that all leases must be written to
>permanent store before being offered to a client - thus avoiding the
>possible situation where a lease is offered, the server dies for
>whatever reason, and then the server offers the same lease to another
>client because it doesn't know about the first offer. Again, this is
>very quick for a log file, but quite slow for an SQL database -
>especially when you consider that you must sync a consistent database
>to disk after each and every update. NB - this requirement is one of
>those that is ignored by most other servers, including Microsofts.
>
>Even if you got around these two problems, ISC do not have
>development staff sitting around looking for things to do and so are
>unlikely to want to put the amount of effort required into what is
>probably a minority feature.
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