Re: To ODA or Not?

From: Jeff Chirco <backseatdba_at_gmail.com>
Date: Fri, 27 Mar 2015 17:11:59 -0700
Message-ID: <CAKsxbLr_83AZ+6ck=+vpNHP9K=2GyaXEp=U8RTM86ZN1UYQ47A_at_mail.gmail.com>

Well we are not licensed for RAC nor will we want to. Is that a requirement? I thought no I had a conversation with the PM at an event and I believe he said you didn't need to use RAC, the second server could be used as a failover which I guess is like RAC but not a full Oracle RAC environment. Maybe that is what you are referring to.

On Fri, Mar 27, 2015 at 5:02 PM, MARK BRINSMEAD <mark.brinsmead_at_gmail.com> wrote:

> You *will* be using RAC, once you move to ODA. Things may have changed
> since the first generation of ODA, but the last time I checked (which was
> the release of the first generation), the use of some-form-of-RAC was
> mandatory. As was the use of Enterprise Edition, even though the hardware
> is "small" enough to qualify for Standard Edition.
>
> RAC-one-node was acceptable at the time, and probably still is now.
> Further, even if your system is built on RAC, nothing requires you to start
> more than one instance per database. If your database has only one
> instance, it might *technically* be a RAC database, but the existence of
> RAC will have no material affect on your applications. You really only see
> significant affects once you have two or more instances running.
>
> On Fri, Mar 27, 2015 at 7:22 PM, Jeff Chirco <backseatdba_at_gmail.com>
> wrote:
>
>> We are not using RAC here.
>>
>> On Fri, Mar 27, 2015 at 4:22 PM, Jeff Chirco <backseatdba_at_gmail.com>
>> wrote:
>>
>>> HI Mladen,
>>> Thank you for this information. This helps. As far as the redo logs, if
>>> you put them on the flash storage drive does that help with concerns to the
>>> snapshots?
>>> I am still unsure how the snapshot technology works on the ODA. Is it
>>> similar to NetApp and using SnapManager for Oracle which basically puts all
>>> the tablespaces in backup mode and then "snaps" the volume and then puts
>>> the tablespaces out of backup mode?
>>>
>>> On Fri, Mar 27, 2015 at 3:18 PM, Mladen Gogala <
>>> dmarc-noreply_at_freelists.org> wrote:
>>>
>>>> On 03/27/2015 05:07 PM, Seth Miller wrote:
>>>>
>>>> Jeff,
>>>>
>>>> You are in luck. The latest release of the ODA uses ACFS for the
>>>> database storage which has snapshot/clone technology similar to NetApp.
>>>> ACFS and all of its snapshotting capabilities are included.
>>>>
>>>> Well, that is not exactly true. ACFS uses COW (Copy-On-Write) snapshots
>>>> which will triple your IO rates on writes. When you write to a file system
>>>> with the snapshot, the machine must:
>>>>
>>>> 1. Read the old data (first I/O operation)
>>>> 2. Write the old data to snapshot pool block (second IO operation)
>>>> 3. write the new data to the FS (third IO operation).
>>>>
>>>> Not all snapshot technologies are created equal. SAN manufacturers like
>>>> NetApp usually use so called "deferred write", while file systems like
>>>> BRTFS, ZFS and ACFS use COW. I would be vewy, vewy cawefull with COW
>>>> snapshots, as they can significantly slow your system down, especially if
>>>> redo logs are on the file system with a snapshot.
>>>>
>>>> --
>>>> Mladen Gogala
>>>> Oracle DBAhttp://mgogala.freehostia.com
>>>>
>>>>
>>>
>>
>

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Received on Sat Mar 28 2015 - 01:11:59 CET