Re: Net8 Lookup Method Options - tnsnames(Local) vs. Hostname vs. Onames/LDAP

Comments embedded

On Sat, 29 Nov 2003 00:28:55 -0600, "Burt Peltier" <burttemp1ReMoVeThIs_at_bellsouth.net> wrote:

>Just looking for some opinions (or please correct me if I am wrong) on this
>subject...
>
>Just my 1 opinion, but it seems most shops could just use the Hostname
>Method for most databases and then have a 2nd fallback method (multiple
>methods easily configured in sqlnet.ora in 1 line) of the simpler
>Local(tnsnames) Method.
>
>The other option of Onames/LDAP seems like overkill for something as simple
>as looking up a database, especially in an Intranet network (most shops?).
>

IIRC, as soon as you have multiple instances on one server, you can't use the hostname method. Hence I assume most shops can't use the hostname method at all.

>1) The Local Method which uses a tnsnames.ora file has problems, but is a
>well known method. It of course has the biggest disadvantage of replication
>at the file system level. Of course, depending on the size of the company,
>the replication could be simple or very complex and problematic.

Usually no tnsnames.ora will be identical, because people want to have their 'own' databases only. Also name resolution using tnsnames.ora is definitely much slower than using onames. Basically, in many orgnisations tnsnames will be a PITA

>
>2) The Hostname Method is by far the simplest to implement and maintain.

Not true.

It
>simply uses the existing DNS IP lookup method. It has the big advantage of
>ZERO client configuration and ZERO extra infrastructure (no Onames or LDAP
>server required and no file system replication required). It also appears to
>be quicker in every case (even when Hosntame is the LAST method to check in
>the sqlnet.ora config file specification - ok just 30 or 40 milliseconds,
>but still quicker).
>
>Of course it has the big disadvantage of requiring use of all defaults for
>things like port number and use of a TCP network. There are a couple of
>other limitations like you cannot use MTS or "failover - some NT/W2K option
>I think - not sure".

Failover has NOTHING to do at all with a specific platform. You are confusing failsafe and failover.
I wouldn't call not being capable to use MTS a 'limitation'. That is just a blatant understatement.
>
>But, aren't most people NOT using these non-default Net8 options and
>therefore Hostname Method would work for most databases? With a simple and
>well understood fall-back method like Local(Tnsnames), would this be a
>problem (used for some emergency or in case a non-default option becomes
>necessary)?
>
>3) Onames (which will be replaced by LDAP storage) seems to have the
>disadvantage of requiring the most extra infrastructure. I say "seems"
>because I sorta remember someone saying it works best with an OID (Oracle
>Internet Directory) LDAP storage . And, I am guessing not that many shops
>have OID implemented for LDAP.
>
>Onames seemed cleaner and less problematic because at least it could be
>stored in an existing database (as opposed to OID which I think should be
>installed in a database dedicated to OID). Also, Onames could cache the
>information in a local file if the Onames storage database was down, which
>again seems to make it also better than the LDAP replacement.
>

Onames *ALWAYS* caches the information, so Onames doesn't need to access the database to resolve a request. The cache file is synchronised at regular configurable intervals, and you can have delegated administration in various regions. Also, you don't need to maintain database links anymore.

>
>

Seems like you don't have any working experience with Onames, and your background is a small company. If you have a larger organizations Onames and/or LDAP is the way to go.

--
Sybrand Bakker, Senior Oracle DBA