<div dir="ltr"><div dir="ltr"><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I have always found this to be more trouble than it is worth - it holds on to out of date information,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><div><br></div><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">https://wiki.samba.org/index.php/Nslcd</a></div><div><br></div><div>(*) obligatory Python reference</div><div><br></div><div><br></div><div><br></div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Sat, 27 Oct 2018 at 04:12, Skylar Thompson <<a href="mailto:skylar.thompson@gmail.com">skylar.thompson@gmail.com</a>> wrote:<br></div><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">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">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>
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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">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">skylar.thompson@gmail.com</a><br>
> 3. mailto:<a href="mailto:Beowulf@beowulf.org" target="_blank">Beowulf@beowulf.org</a><br>
> 4. <a href="http://www.beowulf.org/mailman/listinfo/beowulf" rel="noreferrer" target="_blank">http://www.beowulf.org/mailman/listinfo/beowulf</a><br>
<br>
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<br>
<br>
-- <br>
Skylar<br>
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</blockquote></div>