[Beowulf] Poll - Directory implementation

[John Hearns]

To be clear I am talking about the Name Service Cacheing Daemon
I have always found this to be more trouble than it is worth  - it holds on
to out of date information,
and needs to be restarted when you are debugging things like batch systems
etc.

nslcd is something completely different (*)   and whoever chose similar
names should be forced to watch endless re-runs of the Parrot Sketch.
https://wiki.samba.org/index.php/Nslcd

(*) obligatory Python reference





On Sat, 27 Oct 2018 at 04:12, Skylar Thompson <skylar.thompson at gmail.com>
wrote:

> Good to know - we're still nslcd users so have yet to run into that, though
> are about to make the leap to CentOS 7 where I think we will have to use
> it.
>
> On Sat, Oct 27, 2018 at 03:13:47AM +0100, John Hearns via Beowulf wrote:
> >    Skylar, I believe that nscd does not work well with sssd and I
> disabled
> >    it.
> >    See [1]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise
> >    _linux/6/html/deployment_guide/usingnscd-sssd
> >    I believe that nscd is the work of Auld Nick himself and causes more
> >    problems than it is worth on HPC nodes.
> >    If you want to speed up cacheing with sssd itself you can put its
> local
> >    caches on a RAMdisk. This has the cost of no persistence of course and
> >    uses up RAM which you may prefer to put to better use.
> >
> >    On Sat, 27 Oct 2018 at 00:59, Skylar Thompson
> >    <[2]skylar.thompson at gmail.com> wrote:
> >
> >      On Fri, Oct 26, 2018 at 08:44:28PM +0000, Ryan Novosielski wrote:
> >      > Our LDAP is very small, compared to the sorts of things some
> >      people run.
> >      >
> >      > We added indexes today on uid, uidNumber, and gidNumber and the
> >      problem went away. Didn’t try it earlier as it had virtually no
> >      impact on our testing system for whatever reason, but on a different
> >      testing system and on production, it dropped “ls -al /home/“ from
> >      ~90s to ~5s. I’m not sure if all three were necessary, but I’ll look
> >      back at that later.
> >      >
> >      > We’ve run SSSD from day one, so that eliminates the nscld
> >      question. We also moved CentOS 5.x to SSSD, FYI (I believe there was
> >      someone else with some old systems around). Was pretty painless, and
> >      SSSD eliminates a lot of problems that exist with the older stuff
> >      (including some really boneheaded very large LDAP queries that were
> >      happening routinely with the older nss-ldap software if I’m
> >      remembering its name correctly).
> >      Have you experimented with client-side caching services like nscd?
> >      nscd has
> >      its quirks (in particular, it does very poorly with caching spurious
> >      negative
> >      results from transient network failures), but it also is a big
> >      performance
> >      improvement since you don't even have to hit the network or the
> >      directory
> >      services.
> >      --
> >      Skylar
> >      _______________________________________________
> >      Beowulf mailing list, [3]Beowulf at beowulf.org sponsored by Penguin
> >      Computing
> >      To change your subscription (digest mode or unsubscribe) visit
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> >
> > References
> >
> >    1.
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/usingnscd-sssd
> >    2. mailto:skylar.thompson at gmail.com
> >    3. mailto:Beowulf at beowulf.org
> >    4. http://www.beowulf.org/mailman/listinfo/beowulf
>
> > _______________________________________________
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>
>
> --
> Skylar
> _______________________________________________
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