Re: Big RAC Benchmark Performance Tips?

  • From: "LS Cheng" <exriscer@xxxxxxxxx>
  • To: VIVEK_SHARMA@xxxxxxxxxxx
  • Date: Tue, 1 Aug 2006 22:33:13 +0200

Hi

Is your production going to have same init settings as this?


I am not sure why you set _b_tree_bitmap_plans to FALSE, it does does btree bitmap conversion on btree indexes (you said bitmap indexes?)

You need _system_trig_enabled to be TRUE!

_wait_for_sync and  _check_block_after_checksum by default is true already,
setting wait_for_sync to FALSE is quite dangerous

I was wondering how did you determine 256 for _log_simultaneous_copies?


On 8/1/06, VIVEK_SHARMA <VIVEK_SHARMA@xxxxxxxxxxx> wrote:

Folks



A 4-node RAC BIG benchmark with Oracle 10g / AIX 5.3L using a Hybrid
Banking App. is underway.



*Qs1 Does Cache fusion(Traffic between the nodes thru the interconnects)
continue to be an expensive operation in Oracle 10g? *

To minimize Cache fusion, Manually Transactions have been grouped such
that transactions accessing different DB Server Nodes access different
respective Table partitions (& NOT the same Table partition). Thus Different
Object BLOCKS are accessed in different DB Server nodes.

NOTE – Partitioning of heavier underlying tables has been done such that
different partitions lie in DIFFERENT Tablespaces (& hence datafiles).



*Qs2 Is Low Latency Protocol - LLT protocol (of Veritas) equivalent or
something similar available with GPFS? *

Currently default (UDP) is being used.



NOTE - A Past benchmark done by us on SUN using VXFS (Veritas) with both
Low Latency Protocol (LLT) & User Datagram Protocol (UDP, Default) showed
LLT had a *98%  Lower interconnect utilization* versus UDP.



*Qs3* Any additional init.ora parameters for performance apart from the
following which have been set?



db_writer_processes=16

db_cache_advice=OFF

event='10196 trace name context forever, level 10' (to disable index skip
scan)

_library_cache_advice = FALSE

_log_simultaneous_copies      256

_b_tree_bitmap_plans = FALSE (as NO Bitmap indexes exist)

_check_block_after_checksum   TRUE

_system_trig_enabled          FALSE (Benchmark Has NO need for Triggers)

_wait_for_sync                TRUE





NOTE - Standard features i.e. AUM, Tempfiles & ASSM are being used.



*Qs4 Other best practices to deploy?*





Will provide Statspack, Other diagnostics info. as needed.



Thanks indeed





*Configuration* :-



APP & DB machines – *P5* series

Application Hybrid – (OLTP + Batch nature of Trans).

Oracle 10.2

AIX 5.3

Filesystem GPFS

Storage Box DS8300

Hardware RAID 1+0

Underlying Hardware Stripe Unit Size 64 KB

Overlying Logical Volume Manager Stripe Unit Size 32 MB (S.A.M.E.)


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