RE: Virident FlashMAX SCM

  • From: bill thater <shrekdba@xxxxxxxxx>
  • To: "Goulet, Richard" <Richard.Goulet@xxxxxxxxxxx>, "anthony.ballo@xxxxxxxxxxx" <anthony.ballo@xxxxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 6 Jun 2012 08:49:15 -0700

It takes THAT long?:-(

sent from my Windows Phone
Bill"shrek" thater Oracle DBA
Shrekdna@xxxxxxxxx
"Oh boother said Pooh 'lock phasers on thehefalump. Mr.Piglet meet me
in transporter room three" From: Goulet, Richard
Sent: Wednesday, June 06, 2012 10:03 AM
To: anthony.ballo@xxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: Virident FlashMAX SCM
Darn that myth is still running around?  No you're not missing
anything, but the author certainly is.  Goes along with the individual
who told me that you can drop the system tablespace.  Yes you can, but
your db crashes in about 0.5 mseconds thereafter.

Richard Goulet
Senior Oracle DBA/NA TEAM Lead
PAREXEL International
T 978.495.4127

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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Anthony Ballo
Sent: Tuesday, June 05, 2012 2:59 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Virident FlashMAX SCM

Was reading this white paper from Virident today:
Accelerating Oracle Databases and Reducing Storage Complexity and
Costs. Virident FlashMAX SCM as Primary Storage.


Offered at: 
http://www.bitpipe.com/data/document.do?res_id37280483_183&srcP53040&asrc=EM_BRU_17570135&uid956921


They are making a point that switching from 8k block size to 4k would
reap performance benefits:


When Oracle data is stored on FlashMAX devices, reducing Oracle
database block size from the default value of 8192 bytes (8KB) to 4096
bytes (4KB) can provide substantial performance benefits in many
applications. With HDDs, reading/writing 4KB takes essentially the
same amount of time as 8KB as most of the time is spent on moving
heads. In contrast, FlashMAX can perform 2x the amount of IOPS with
4KB block size compared to 8KB block size, or the same amount of IOPS
at lower latencies.


They offered the steps on how to change your block size:

You can set this parameter in several different ways:

 1.  By adding it to initORACLE_SID.ora file (or changing if the
parameter already exists)  2.  By setting the parameter in the SPFILE:
    *   SQL>alter system set db_block_size@96 scope=spfile;
    *   SQL>shutdown immediate
    *   SQL>startup
 3.  By setting it on Initialization Parameters -> Sizing tab of the DBCA

Last I checked, you could only change the default block size at DB
creation. Sure you can have multiple block sizes supported at the
Tablespace level (must also specify cache sizes) but it's not as
simple as changing a init parameter and bouncing your instance -
otherwise, you will see:

ORA-00209: control file blocksize mismatch, check alert log for more info

Hard to take this white paper seriously or am I missing something?


Anthony




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