Re: Exadata Cacheflash Compression

cellcli -e list cell detail | grep flashCacheCompress

         flashCacheCompress: TRUE

And if you follow the directions in the note, you will actually see the difference in size like:

This is on an X3-2:

cellcli -e list flashcache detail | grep effectiveCacheSize effectiveCacheSize: 1488.75G

And after enabling the compression:

cellcli -e list flashcache detail | grep effectiveCacheSize  effectiveCacheSize: 2978.75G

Hope this helps your understanding!

Carol Dacko
Enkitec

On Fri, May 9, 2014 at 10:20 AM, K Gopalakrishnan <kaygopal_at_gmail.com>wrote:

> Tom,
>
> Try CELLCLI list flashcache attributes all.
>
> -Gopal
>
>
>
>
> On Fri, May 9, 2014 at 8:37 AM, Thomas P S <dmarc-noreply_at_freelists.org>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_at_freelists.org> wrote:
>> As Carol said, you're correct. I should have been more specific.
>>
>> ------------------------------
>> *From:* George Leonard - Business Connexion <George.Leonard_at_bcx.co.za>
>> *To:* "dmarc-noreply_at_freelists.org" <dmarc-noreply_at_freelists.org>
>> *Cc:* ORACLE- L <oracle-l_at_freelists.org>; Roy <royxavier_at_yahoo.com>
>> *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_at_bcx.co.za <george.leonard_at_oracle.com>
>> Web: http://www.bcx.com <george.leonard_at_oracle.com>
>>
>>
>> On 08 May 2014, at 5:26 PM, Craig Dickman <dmarc-noreply_at_freelists.org>
>> 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_at_freelists.org>
>> *To:* ORACLE- L <oracle-l_at_freelists.org>; Roy <royxavier_at_yahoo.com>
>> *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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