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Any need for nscd?

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Paul Cocker

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Aug 27, 2008, 3:10:12 AM8/27/08
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On a server running BIND, is there any need for nscd (a name caching
daemon)?

Paul Cocker

TNT Post is the trading name for TNT Post UK Ltd (company number: 04417047), TNT Post (Doordrop Media) Ltd (00613278), TNT Post Scotland Ltd (05695897),TNT Post North Ltd (05701709) and TNT Post South West Ltd (05983401). Emma's Diary and Lifecycle are trading names for Lifecycle Marketing (Mother and Baby) Ltd (02556692). All companies are registered in England and Wales; registered address: 1 Globeside Business Park, Fieldhouse Lane, Marlow, Buckinghamshire, SL7 1HY.


Niall O'Reilly

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Aug 27, 2008, 4:28:33 AM8/27/08
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On Wed, 27 Aug 2008 08:10:12 +0100, Paul Cocker
<paul....@tntpost.co.uk> wrote:

> On a server running BIND, is there any need for nscd (a name caching
> daemon)?

Very likely not, but
without knowing your requirements, who can say?

Niall O'Reilly

Paul Cocker

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Aug 27, 2008, 4:28:11 AM8/27/08
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Well as nscd offers nothing but name caching, I'm not sure what
confusion could lie as regards my requirements. I wish my server to have
name caching capabilities and, as stated it will already be running
BIND, therefore is this something BIND can handle (therefore no need to
add an additional package), or is it outside the scope of BIND and I
should add nscd to the server to handle this function.

Please let me know if I need to provide any further details.

Paul Cocker

Niall O'Reilly


Milan Jurik

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Aug 27, 2008, 5:17:03 AM8/27/08
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Hi Paul,

depending on your operating system, nscd is caching naming data (passwd,
group, hosts and other naming databases) as client, it has no direct
relevance to BIND nor DNS clients of your BIND.

It can improve performance of your server, but if your server is just
for BIND, then impact isn't measurable probably.

Best regards,

Milan

V st, 27. 08. 2008 v 10:28, Paul Cocker píše:

Paul Cocker

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Aug 27, 2008, 6:49:38 AM8/27/08
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Ah, it's clear I have mis-understood the nature of this program, I had taken it to mean DNS name caching. In that case I will investigate it further.

Many thanks,

Kevin Darcy

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Aug 27, 2008, 5:00:10 PM8/27/08
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nscd's host name caching is evil, and, at the very least, we disable the
"hosts" cache of nscd on every machine we deploy.


- Kevin

Paul Cocker wrote:
> Ah, it's clear I have mis-understood the nature of this program, I had taken it to mean DNS name caching. In that case I will investigate it further.
>
> Many thanks,
>
> Paul Cocker
>
> -----Original Message-----
> From: Milan...@Sun.COM [mailto:Milan...@Sun.COM]
> Sent: 27 August 2008 10:17
> To: Paul Cocker
> Cc: bind-...@isc.org
> Subject: RE: Any need for nscd?
>
> Hi Paul,
>
> depending on your operating system, nscd is caching naming data (passwd, group, hosts and other naming databases) as client, it has no direct relevance to BIND nor DNS clients of your BIND.
>
> It can improve performance of your server, but if your server is just for BIND, then impact isn't measurable probably.
>
> Best regards,
>
> Milan
>

> V st, 27. 08. 2008 v 10:28, Paul Cocker p�e:

Gary Mills

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Aug 27, 2008, 8:37:44 AM8/27/08
to
In <g936hq$30ds$1...@sf1.isc.org> Milan Jurik <Milan...@Sun.COM> writes:

>depending on your operating system, nscd is caching naming data (passwd,
>group, hosts and other naming databases) as client, it has no direct
>relevance to BIND nor DNS clients of your BIND.

We disable the hosts cache in /etc/nscd.conf but leave all the other
caches like this:

enable-cache hosts no

`nscd -g' will give you statistics on all of the caches.

--
-Gary Mills- -Unix Support- -U of M Academic Computing and Networking-

Stacey Jonathan Marshall

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Sep 2, 2008, 6:58:20 AM9/2/08
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Kevin Darcy wrote:
> nscd's host name caching is evil, and, at the very least, we disable the
> "hosts" cache of nscd on every machine we deploy.
>

Don't shoot....

May I ask why you consider it to be evil?

Is it that it prevents round-robin?
Or that it broke TTL (which is now fixed)?
Or simply that it prevents users from specifying RES_OPTIONS,
LOCALDOMAIN and HOSTALIASES.

Regards

Stacey Marshall
Sun Microsystems


>
> - Kevin
>
> Paul Cocker wrote:
>
>> Ah, it's clear I have mis-understood the nature of this program, I had taken it to mean DNS name caching. In that case I will investigate it further.
>>
>> Many thanks,
>>
>> Paul Cocker
>>
>> -----Original Message-----
>> From: Milan...@Sun.COM [mailto:Milan...@Sun.COM]
>> Sent: 27 August 2008 10:17
>> To: Paul Cocker
>> Cc: bind-...@isc.org
>> Subject: RE: Any need for nscd?
>>
>> Hi Paul,
>>

>> depending on your operating system, nscd is caching naming data (passwd, group, hosts and other naming databases) as client, it has no direct relevance to BIND nor DNS clients of your BIND.
>>

>> It can improve performance of your server, but if your server is just for BIND, then impact isn't measurable probably.
>>
>> Best regards,
>>
>> Milan
>>

>> V st, 27. 08. 2008 v 10:28, Paul Cocker píše:

Kevin Darcy

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Sep 2, 2008, 8:05:07 PM9/2/08
to
Any or all of those.

It's really not that resource-intensive to run a simple caching-only
nameserver, and it provides options (e.g. stub zones, slaving for
redundancy/performance, selective forwarding for performance
optimization or to deal with certain pathological connectivity/topology
scenarios, tuning of cache size, cleaning etc.) that may be useful in
the future.

What value does nscd offer that one would prefer to use it for local
caching of name lookups?


- Kevin

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