Re: automating database creation
Date: Mon, 17 Aug 2020 15:48:15 +0200
Message-ID: <CALSQGr+QCMm_CHOxCSrgN8mwJW3jhbhuq8vGz-u-K7FY3a1VEA_at_mail.gmail.com>
I fully agree with all your points.
About your questions...
> Just to check if I correctly understood your anti-micromanagements
> strategy: because of the 1:1 relationship between file system and the disk
> group, every ACFS snapshot will always contain all the databases stored in
> the disk group, right?
No, When you have your empty filesystem, you create an empty snapshot per database.
E.g.
ORCLA -> datafiles of ORCLA
ORCLB -> datafiles of ORCLB
In the base of the filesystem you should not put anything, so at each new database you can create an empty starting snapshot.
Then, when you need to create a snapshot of ORCLA, you create a snapshot of snapshot (e.g. ORCLA_snap). At that point, ORCLA and ORCLA_snap will contain only pointers to extents containing just ORCLA data, not ORCLB data.
I hope it is clearer :-)
I noticed in
> https://www.slideshare.net/ludovicocaldara/how-to-bake-a-customer-story-with-with-windows-nvme-data-guard-acfs-snapshots-perl
> that the primary database wasn’t using ACFS. What was the reason for
> that?
1st concern: stability of ACFS on Windows... we preferred to keep the
primary site on ASM to avoid problems
2nd concern: with ACFS you typically lose 3-5% of performance, we wanted to
get the most out of the NVM-e cards :-)
-- Ludo Il giorno lun 17 ago 2020 alle ore 14:38 Noveljic Nenad < nenad.noveljic_at_vontobel.com> ha scritto:Received on Mon Aug 17 2020 - 15:48:15 CEST
> Hi Ludovico,
>
>
>
> Avoiding ACFS space micromanagement was one of my concerns while reading
> the documentation. The problem is the mandatory volume size. ZFS doesn’t
> require that – it is thinly provisioned from the zpool (zpool is the
> counterpart of the disk group in ACFS).
>
>
>
> Just to check if I correctly understood your anti-micromanagements
> strategy: because of the 1:1 relationship between file system and the disk
> group, every ACFS snapshot will always contain all the databases stored in
> the disk group, right?
>
>
>
> I noticed in
> https://www.slideshare.net/ludovicocaldara/how-to-bake-a-customer-story-with-with-windows-nvme-data-guard-acfs-snapshots-perl that
> the primary database wasn’t using ACFS. What was the reason for that?
>
>
>
> By the way, this solution looks very similar to ours, except that we’ve
> used Solaris/ZFS instead of Windows/ACFS. We’ve developed the automation in
> Perl, too. But it was 10 years ago. We’ll switch to Python for the new
> platform. People are generally more motivated to learn Python, because it
> opens up some new career opportunities.
>
>
>
> You mentioned unknown fragmentation performance impact due to
> copy-on-write snapshots on slide 58 in
> https://www.slideshare.net/ludovicocaldara/oracle-database-on-acfs-a-perfect-marriage.
> Bart Sjerps described the way to measure this overhead:
> https://bartsjerps.wordpress.com/2013/02/26/zfs-ora-database-fragmentation/
> .
>
>
>
> Best regards,
>
>
>
> Nenad
>
> https://nenadnoveljic.com/blog/about/
> <https://urldefense.com/v3/__https:/nenadnoveljic.com/blog/about/__;!!GvC3Dl69FG1X3k3XzQ!KZ-YtPjOpVdKpz3XqsB6VQJHXbGyHr_h57YFQFFviDiZM22g94_c6JpozP7S4lBodw$>
>
>
>
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