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<div class="moz-cite-prefix">On 10/27/2018 03:08 AM, John Hearns via
Beowulf wrote:<br>
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<div>To be clear I am talking about the Name Service Cacheing
Daemon</div>
<div>I have always found this to be more trouble than it is
worth - it holds on to out of date information,</div>
<div>and needs to be restarted when you are debugging things
like batch systems etc.</div>
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<br>
My favorite feature of nscd was the paranoid option: <br>
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<p>
<b>paranoia</b>
<i><yes|no></i>
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<dt><br>
</dt>
<dd>
Enabling paranoia mode causes nscd to restart itself
periodically.
The default is no.
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<br>
In practice, you need this. Otherwise, nscd will eventually hang,
requiring you to login as root and manually restart nscd. When you
see software with a feature like this, you know it's unreliable. <br>
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<div>nslcd is something completely different (*) and whoever
chose similar names should be forced to watch endless
re-runs of the Parrot Sketch.</div>
<div><a href="https://wiki.samba.org/index.php/Nslcd"
moz-do-not-send="true">https://wiki.samba.org/index.php/Nslcd</a></div>
<div><br>
</div>
<div>(*) obligatory Python reference</div>
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<br>
Well, that corrects my statement in my last e-mail. nslcd always
looked just like nscd to me. <br>
<br>
Prentice<br>
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<div dir="ltr">On Sat, 27 Oct 2018 at 04:12, Skylar Thompson
<<a href="mailto:skylar.thompson@gmail.com"
moz-do-not-send="true">skylar.thompson@gmail.com</a>>
wrote:<br>
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<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Good to know
- we're still nslcd users so have yet to run into that, though<br>
are about to make the leap to CentOS 7 where I think we will
have to use<br>
it.<br>
<br>
On Sat, Oct 27, 2018 at 03:13:47AM +0100, John Hearns via
Beowulf wrote:<br>
> Skylar, I believe that nscd does not work well with
sssd and I disabled<br>
> it.<br>
> See [1]<a
href="https://access.redhat.com/documentation/en-us/red_hat_enterprise"
rel="noreferrer" target="_blank" moz-do-not-send="true">https://access.redhat.com/documentation/en-us/red_hat_enterprise</a><br>
> _linux/6/html/deployment_guide/usingnscd-sssd<br>
> I believe that nscd is the work of Auld Nick himself
and causes more<br>
> problems than it is worth on HPC nodes.<br>
> If you want to speed up cacheing with sssd itself you
can put its local<br>
> caches on a RAMdisk. This has the cost of no
persistence of course and<br>
> uses up RAM which you may prefer to put to better use.<br>
> <br>
> On Sat, 27 Oct 2018 at 00:59, Skylar Thompson<br>
> <[2]<a href="mailto:skylar.thompson@gmail.com"
target="_blank" moz-do-not-send="true">skylar.thompson@gmail.com</a>>
wrote:<br>
> <br>
> On Fri, Oct 26, 2018 at 08:44:28PM +0000, Ryan
Novosielski wrote:<br>
> > Our LDAP is very small, compared to the sorts
of things some<br>
> people run.<br>
> ><br>
> > We added indexes today on uid, uidNumber, and
gidNumber and the<br>
> problem went away. Didn’t try it earlier as it had
virtually no<br>
> impact on our testing system for whatever reason,
but on a different<br>
> testing system and on production, it dropped “ls -al
/home/“ from<br>
> ~90s to ~5s. I’m not sure if all three were
necessary, but I’ll look<br>
> back at that later.<br>
> ><br>
> > We’ve run SSSD from day one, so that eliminates
the nscld<br>
> question. We also moved CentOS 5.x to SSSD, FYI (I
believe there was<br>
> someone else with some old systems around). Was
pretty painless, and<br>
> SSSD eliminates a lot of problems that exist with
the older stuff<br>
> (including some really boneheaded very large LDAP
queries that were<br>
> happening routinely with the older nss-ldap software
if I’m<br>
> remembering its name correctly).<br>
> Have you experimented with client-side caching
services like nscd?<br>
> nscd has<br>
> its quirks (in particular, it does very poorly with
caching spurious<br>
> negative<br>
> results from transient network failures), but it
also is a big<br>
> performance<br>
> improvement since you don't even have to hit the
network or the<br>
> directory<br>
> services.<br>
> --<br>
> Skylar<br>
> _______________________________________________<br>
> Beowulf mailing list, [3]<a
href="mailto:Beowulf@beowulf.org" target="_blank"
moz-do-not-send="true">Beowulf@beowulf.org</a> sponsored by
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> Computing<br>
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> <br>
> References<br>
> <br>
> 1. <a
href="https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/usingnscd-sssd"
rel="noreferrer" target="_blank" moz-do-not-send="true">https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/usingnscd-sssd</a><br>
> 2. mailto:<a href="mailto:skylar.thompson@gmail.com"
target="_blank" moz-do-not-send="true">skylar.thompson@gmail.com</a><br>
> 3. mailto:<a href="mailto:Beowulf@beowulf.org"
target="_blank" moz-do-not-send="true">Beowulf@beowulf.org</a><br>
> 4. <a
href="http://www.beowulf.org/mailman/listinfo/beowulf"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://www.beowulf.org/mailman/listinfo/beowulf</a><br>
<br>
> _______________________________________________<br>
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<br>
<br>
-- <br>
Skylar<br>
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