RE: DISK configuration - help please.

I already answered this, but...........

Raid 5 is fine for selects (as someone else said is these posts) put the problems arise when inserts, updates, and deletes are done on them. If you have a On-Line Transaction Processing database, with millions of inserts per minute (a friend used to work for a phone company and they tracked and worked with all the calling card calls going on around the US) then writing to a datafile that is mirrored on 2 or 3 or 4 disks plus any extra disks for that parity bit (as you can see I'm still not totally up on the SysAdmin terms for these raid configurations :)), that's a lot of place to be writing information when doing those kinds of DML processes. Not to mention Redo Log being written too even more then that!

Woo-Hoo!

Anyways, that's it.

Lyall Barbour

At 11:26 AM 8/18/00 -0800, you wrote:
>I have done benchmarking for full table scan (select count(*) from
>tablename --- 4.7 millions records) for the same table and same storage
>parameter in different configurations :
>1. For Raid5 (5 disk + 1 parity) : 14 seconds.
>2. For Striped 3 disks : 33 seconds.
>3. For Plain disks (2 disks concatenated, unfortunately with different
>file system type) : 87 seconds.
>
>So, why dont you use Raid5....?
>
>Rivaldi
>
>
>>----- Original Message -----
>>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>>Sent: Thursday, August 17, 2000 11:14 AM
>>
>>
>> > Get rid of RAID 5.
>> >
>> > Lyall
>> >
>> > At 06:46 AM 8/17/00 -0800, you wrote:
>> >
>> > >I am in the process of building two DB servers - one live and the other
>> > >standby. We are not overly concerned with disk capacity - but rather
>>with
>> > >speed of access.
>> > >
>> > >Our current configuration is
>> > >
>> > >primary has 10 disks in RAID 0+1
>> > >standby has 6 disks in RAID 5
>> > >
>> > >This is to give us 5 physical devices for production - I think a holdover
>>of
>> > >OFA guidelines.
>> > >
>> > >What I am looking for is a bit of advice on the best optin for current
>> > >configurations. I can add disks to this later. I am also using Veritas
>>VM
>> > >and FS and so can relayout my RAID 5 to RAID 0+1 pretty easily as well.
>> > >Adding disks to the system is also a breaze.
>> > >
>> > >All of these disks are in one FS mounted to /u01 .. .for easy management
>>on
>> > >our site we elected one mount point and one very expandable FS.
>> > >
>> > >I am considering breaking my configuration and going with 8 disks in 0+1
>>for
>> > >both systems - or going with 10 and 6 but both in 0+1 - I don't think
>>that
>> > >RAID 5 is a good idea ever - even for a standby system, but there is some
>> > >pressure to have 5 physical devices and RAID 5 with 6 gives us that
>>too...
>> > >
>> > >
>> > >Anybody out there willing to throw two cents my way?
>> > >
>> > >
>> > >thanks!
>> > >
>> > >adam
>> > >--
>> > >Author: Adam Turner
>> > > INET: ATurner_at_concretemedia.com
>> > >
>> > >Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
>> > >San Diego, California -- Public Internet access / Mailing Lists
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>> > >(or the name of mailing list you want to be removed from). You may
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>> >
>> > --
>> > Author: Lyall Barbour
>> > INET: lbarbour_at_stanford.edu
>> >
>> > Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
>> > San Diego, California -- Public Internet access / Mailing Lists
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>> >
>>
>>--
>>Author: Steve McClure
>> INET: steve_at_pactr.com
>>
>>Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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>>--
>>Author: Richard Ji
>> INET: richard_at_letsplay.com
>>
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>
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>--
>Author: Rivaldi Bahar
> INET: rivaldi_bahar_at_hotmail.com
>
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Received on Fri Aug 18 2000 - 14:43:17 CDT