Re: new database server build - sanity check

From: Mark Burgess <mark_at_burgess-consulting.com.au>
Date: Tue, 29 Jan 2013 11:34:29 +1100
Message-Id: <F03B340E-31C7-41EC-ACC4-C165F5874ACC_at_burgess-consulting.com.au>



We have been working with ZFS on a large BI environment for past 2 years. Just a few observations that you can add to the excellent points already made from others on this list:
  • if your workload is mostly read then you can tune the related ZFS kernel parameters to cap the amount of memory that the ZFS ARC will use.
  • if your workload is mostly write or you have periods of intense writing then you can look at using SSD devices for the ZFS ZIL as a part of your build.
  • ZFS can push the kernel CPU utilisation up when writing - during periods of intense writing..ie..RMAN backup..we can see the kernel CPU utilisation going up to 40% so you need to allow for this additional overhead.
  • the snapshot features are excellent for cloning. We can clone a multi TB database in a matter of minutes - this is something that may be of significant benefit to some sites without having to perform an RMAN duplicate or similar.
  • you need to leave at least 20% free in the zpool otherwise write performance degrades significantly.

If you can balance up what the intended workload and operational requirements will be for this application against what ASM or ZFS can provide then one should become the best fit for requirement.

Regards,

Mark

On 29/01/2013, at 2:20 AM, "Patterson, Joel" <Joel.Patterson_at_crowley.com> wrote:

> The snapshot capabilities can be a nice feature. You can snap a live database and restore it back within moments -- eliminating the time needed for an RMAN restore.
>
> Having said that, I would look into testing some things -- perhaps Google "ZFS evil tuning guide" -- Note however, that there are also websites out there that discount much of what is in the guide, essentially saying to leave the defaults or most of them, hence some testing first. The foundation you lay will be the one you will be using.
>
>
>
> Joel Patterson
> Database Administrator
> 904 727-2546
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of ~Jeff~
> Sent: Thursday, January 24, 2013 7:15 PM
> To: Oracle-L_at_freelists.org
> Subject: new database server build - sanity check
>
> Hi all
> Your opinions please!
>
> We are embarking on a new database server build - the sysadmin is keen on Solaris 11.1 and ZFS on the T4-1 server. We will use zones for environment segregation and license mitigation.
>
> While I've used sol9 and 10 without absolutely no issues before, using such a new OS version with a relatively non-mainstream filesystem seems ...
> adventurous.
>
> Am I being too apprehensive, or is this a reasonable concern ? I'm interested in any real-life experience, rather than the marketing bullet points. Discuss. :)
>
> thanks in advance -
> Jeff
>
>
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Received on Tue Jan 29 2013 - 01:34:29 CET

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