Oracle-L: Re: Sizing - RAC, storage subsystem EMC

From: Waleed Khedr <wkhedr_at_attbi.com>
Date: Tue, 20 May 2003 05:01:46 -0800
Message-ID: <F001.0059DA32.20030520050146@fatcity.com>

Do not use raid 5.
Implement EMC hardware striping (RAID 0 + 1 ).
Read about table compression in Oracle 9.2 if the data in the table will be static. You can easily cut the storage requirements by 70%.

Regards,

Waleed

Original Message ----- From: George.Leonard_at_za.didata.com To: Multiple recipients of list ORACLE-L Sent: Tuesday, May 20, 2003 3:06 AM Subject: Sizing - RAC, storage subsystem EMC

Hi all, hope you can give some input ideas.

I am in the process of designing a system for a client of ours for a proposal

The sizing information I have been given is as follows.

58.1 million tickets/day at 351 bytes per record. The record was complete populated (all columns filled to max) in a table and then analyzed. Average row size 351 bytes.

=~ 19 GB/day. Raw data. Plus overhead (indexes, temp space, rollback, some other data etc) here and there I have requested 5 TB.

We need to keep records for a month. Table design I am looking at is a date partition with a second level hash partition. This is so that I can move data in the oldest week/table space off line and write them to optical storage for possible retrieval at a later date (requirement).

Of course this will be on locally managed table spaces with auto storage management for segments.

Hardware:

The database will be a Oracle RAC 9.2.0.4 on Sun cluster 3 build on 2 x Sun StarFire V880, 4 CPU's, 4 GB RAM each,

Connected to an EMC SAN via Fiber Channel

I do not have more information about the EMC array at the moment. Hitachi has been mentioned. (excuse the spelling)

Question I have.

I have been asked how many writes the Database will be doing to the SAN per second.

I have determined that I should expect about 2000 tickets/second.

The table in question will have 2 indexes.

Now following rough guessing I said I should expect at least 16 000 writes/second

This was done by say/assuming

2 writes for the redo log files (2 members)

2 writes for the control files (2 control files)

2 writes to index blocks

1 write to undo table space block

1 write to table block for data

total 8 blocks written to per ticket.

Now I know the above is a real rough. And probably very wrong, if someone can shed some more light on it and give me a more accurate method/guess I would appreciate it.

Another question.

The hardware SAN engineers are telling me they want to configure the SAN in a RAID 5 configuration. I have requested Raid 0 + 1. They say this is going to be to expensive and the new technology allows them to give me the performance I want using RAID 5.

I would prefer to err on the side of caution and follow Oracle industry wide recommendation and follow the SAME methodology.

Comment.

Thx.

George

George Leonard

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Author: Waleed Khedr
INET: wkhedr_at_attbi.com

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