ADSM-L

Re: [ADSM-L] Deduplication

2017-04-12 11:58:00
Subject: Re: [ADSM-L] Deduplication
From: Stefan Folkerts <stefan.folkerts AT GMAIL DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Wed, 12 Apr 2017 17:55:43 +0200
Eric,

The containerpool has a reuse delay setting in day's that, in effect, works
the same as the reuse delay on traditional storagepools, did you set this
to 0? It's in day's not hours and the default is 1.

Regards,
   Stefan


On Tue, Apr 11, 2017 at 2:21 PM, Loon, Eric van (ITOPT3) - KLM <
Eric-van.Loon AT klm DOT com> wrote:

> Hi Dave!
> Thank you very much for your reply!
> I deleted some data this morning and waited for 4 hours before making a
> new backup, but that doesn't seem to be enough. Is there any way to
> influence this waiting period? A certain table reorg or stop/start of the
> server or is it just hard-coded?
> Thanks again for your help!
> Kind regards,
> Eric van Loon
> Air France/KLM Storage Engineering
>
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf 
> Of
> Del Hoobler
> Sent: maandag 10 april 2017 18:12
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: Deduplication
>
> Hi Eric,
>
> A few things:
>
> - Client-side provides better overall throughput for Spectrum Protect
> because the deduplication is spread across more CPU's. So if you can afford
> to do the deduplication client-side, that is the best overall result.
>
> - Client-side helps reduce network traffic
>
> - The algorithms on how deduplication is performed are the same between
> client and server.
>
>
> The behavior you are seeing has to do with the reusedelay impact on
> deduplicated chunks. If the reusedelay is 1 day (default), that means
> Spectrum Protect keeps the deduplicated chunks pinned in storage until
> that time has passed. If the reusedelay is 0, there is a still a small
> cushion window that might allow the chunks to still be linked to. If you
> waited for a couple of hours AFTER the deletion occurred, I would not
> expect those chunks to be reused.
>
>
>
> Del
>
> ----------------------------------------------------
>
> "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 04/10/2017
> 10:57:27 AM:
>
> > From: "Loon, Eric van (ITOPT3) - KLM" <Eric-van.Loon AT KLM DOT COM>
> > To: ADSM-L AT VM.MARIST DOT EDU
> > Date: 04/10/2017 11:01 AM
> > Subject: Deduplication
> > Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
> >
> > Hi guys!
> > We are trying to make a fair comparison between server-  and client-
> > side deduplication. I'm running into an 'issue' where I notice that
> > once you created a backup of a certain set of data, it is always
> > deduplicated 100% afterwards when you start a new client-side
> > deduped backup. Even when you delete all previous backup on the server
> first!
> > So I backed up a directory, retrieved all objectids through a select
> > * from backups and deleted all objects, but still a new backup is
> > deduplicated 100%. I don't understand why. I though it maybe had
> > something to do with data still being in the container pool, but
> > even with reusdelay=0, everything is deduplicated...
> > Thanks for any help (Andy? :)) in advance.
> > Kind regards,
> > Eric van Loon
> > Air France/KLM Storage Engineering
> > ********************************************************
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> For information, services and offers, please visit our web site:
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> confidential and privileged material intended for the addressee only. If
> you are not the addressee, you are notified that no part of the e-mail or
> any attachment may be disclosed, copied or distributed, and that any other
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> Koninklijke Luchtvaart Maatschappij NV (KLM), its subsidiaries and/or its
> employees shall not be liable for the incorrect or incomplete transmission
> of this e-mail or any attachments, nor responsible for any delay in receipt.
> Koninklijke Luchtvaart Maatschappij N.V. (also known as KLM Royal Dutch
> Airlines) is registered in Amstelveen, The Netherlands, with registered
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