Re: Exadata Cacheflash Compression
- From: K Gopalakrishnan <kaygopal@xxxxxxxxx>
- To: dmarc-noreply@xxxxxxxxxxxxx
- Date: Fri, 9 May 2014 09:20:20 -0500
Tom,
Try CELLCLI list flashcache attributes all.
-Gopal
On Fri, May 9, 2014 at 8:37 AM, Thomas P S <dmarc-noreply@xxxxxxxxxxxxx>wrote:
> That made me to ask one more question: The above MOC Doc saying
>
> Flash cache compression dynamically increases the logical capacity of the
> flash cache by transparently compressing user data as it is loaded into the
> flash cache. This allows much more data to be kept in flash, and decreases
> the need to access data on disk drives.
>
>
> So, it is increasing the logical capacity of the flash cache by
> transparently compressing the user data and never said the capacity is
> getting doubled. So, are we really right to say that my 20TB FC will be
> 40TB after compression or only store the data compressed so that I can
> store more? Also, how can I see the current FC is compressed or not?
>
> Thanks,
> Thomas
> On Friday, May 9, 2014 6:53 PM, Craig Dickman <
> dmarc-noreply@xxxxxxxxxxxxx> wrote:
> As Carol said, you're correct. I should have been more specific.
>
> ------------------------------
> *From:* George Leonard - Business Connexion <George.Leonard@xxxxxxxxx>
> *To:* "dmarc-noreply@xxxxxxxxxxxxx" <dmarc-noreply@xxxxxxxxxxxxx>
> *Cc:* ORACLE- L <oracle-l@xxxxxxxxxxxxx>; Roy <royxavier@xxxxxxxxx>
> *Sent:* Friday, May 9, 2014 4:29 AM
> *Subject:* Re: Exadata Cacheflash Compression
>
> Hi Craig
>
> You say with X4... is this not a way of behaviour thats associated more
> with a SW release number, compared to a HW model/range?
>
>
> Yours Sincerely
>
> ________________________________________
> *George Leonard*
> *Oracle Engineered System Specialist*
>
> Mobile: +27.82 655 2466
> eMail: george.leonard@xxxxxxxxx <george.leonard@xxxxxxxxxx>
> Web: http://www.bcx.com <george.leonard@xxxxxxxxxx>
>
>
> On 08 May 2014, at 5:26 PM, Craig Dickman <dmarc-noreply@xxxxxxxxxxxxx>
> wrote:
>
> Here's how I understand it. The data in flashcache is compressed by
> default anyway, it happens automatically. Prior to X4, the data in the
> flashcache would get compressed but the extra space made available by this
> compression was not usable.
>
> With the release of X4, Oracle gives you the ability to enable
> flashcache compression which essentially gives you the ability to use the
> space freed up by the automatic flashcache compression. Basically, you
> turn 20TB of flash cache into 40TB usable if you have Advanced Compression.
>
>
> ------------------------------
> *From:* Thomas P S <dmarc-noreply@xxxxxxxxxxxxx>
> *To:* ORACLE- L <oracle-l@xxxxxxxxxxxxx>; Roy <royxavier@xxxxxxxxx>
> *Sent:* Thursday, May 8, 2014 6:29 AM
> *Subject:* Exadata Cacheflash Compression
>
> Dear List,
>
> We have X4-2 Half Rack with 20TB flash cache with database size 8TB. I
> am very reluctant to enable flashcache compression as the size of the
> database is half of flashcache, but Oracle says enabling flashcache
> compression is a best practice. Every code execution need time, even
> though FC is implemented in hardware level compression, still I believe,
> there will be a penalty. In this scenario, enabling flashcache compression
> is a wise idea? Any one got falshcache I/O performance test results with
> compression and with out?
>
> Note: License is not an issue as we have Advanced Compression license.
>
> Thanks in advance,
> Thomas Saviour
>
>
>
>
>
>
>
>
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