Return-Path: Received: from ensim.rackshack.net (root@localhost) by orafaq.net (8.11.6/8.11.6) with ESMTP id hAK1vUm14579 for ; Wed, 19 Nov 2003 19:57:30 -0600 X-ClientAddr: 66.27.56.212 Received: from www3.fatcity.com (rrcs-west-66-27-56-212.biz.rr.com [66.27.56.212]) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id hAK1vHc14565 for ; Wed, 19 Nov 2003 19:57:17 -0600 Received: (from root@localhost) by www3.fatcity.com (8.11.6/8.11.6) id hAJN0Uv24269 for oracle-l@orafaq.net; Wed, 19 Nov 2003 15:00:30 -0800 Received: by fatcity.com (05-Jun-2003/v1.0g-b73/bab) via fatcity.com id 005D7321; Wed, 19 Nov 2003 15:00:14 -0800 Message-ID: Date: Wed, 19 Nov 2003 15:00:14 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: Jared.Still@radisys.com Sender: ml-errors@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: Jared.Still@radisys.com Subject: Re: FW: SAN configuration for Banner Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0g, build 73; ListGuru (c) 1996-2003 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="=_alternative 007DFA3388256DE3_=" --=_alternative 007DFA3388256DE3_= Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Paul, just curious why RAID 01 rather than RAID 10. RAID 10 is much more resistant to disk failures that RAID 01. 10 drives in a RAID 01 with drives having a MTBF of say 100,000 hours. ( don't know if the 100k is low or high ) Each stripe in the RAID 01 has a MTBF of 20k hours, which is 10k hours for the array as a whole. In a RAID 10 each mirrored pair would have an MTBF of 50k hours, which also appears to give an MTBF of 10k hours, but this is where statistics are misleading. Lose one drive on each side of the RAID01 and is down. The RAID 10 could lose 5 up to drives, as long as each failure is only one side of a mirrored pair, and still stay up. Even more beneficial, in the RAID 01 if you lose on drive, you will lose 50% of read throughput. Losing a single drive in the RAID 10 will cost you about 10% throughput. If Matthew Zito is still here, he can no doubt enlighten us with no end of detail on the subject. Jared Paul Drake Sent by: ml-errors@fatcity.com 11/19/2003 12:20 PM Please respond to ORACLE-L =20 To: Multiple recipients of list ORACLE-L cc:=20 Subject: Re: FW: SAN configuration for Banner Sam, =20 Dell was perfectly happy to configure the following for me on a CX200=20 unit: (2 trays of 15 drives, 1 tray 36 GB 15K, 1 tray 73 GB 10K, 1 hot spare per = tray) =20 3 x RAID 1 for online redo logs (members a,b,c, 6 drives total) 2 x RAID 01 for datafiles (8 drives each, 16 drives total) 1 x RAID 1 for archlogs (2 drives) 1 x RAID 01 for undo (4 drives) =20 we used less than half of the available storage, saving that for when=20 another system is migrated to this unit. when creating filesystems, we did = not format the entire RAID vols for live files, and created filesystems=20 for storing local backup sets. =20 You will like having datafiles on 8 drive RAID 01 (or RAID 10) volumes. RMAN backups fly like you would not believe. =20 hth. =20 Paul Sam Bootsma wrote: Hi List, =20 We are approaching the cusp of a decision on how to store Oracle data=20 files on our SAN. We don't have the SAN yet, but it is due to arrive any=20 week (if not any day).=20 =20 I passed Cary's "Is RAID 5 Really a Bargain?" paper to our Sys Admin,=20 which he read and succinctly summarized for the Technical Manager here. I = have also read through a couple of papers referenced in the BAARF site.=20 The Sys Admin comments were: =20 Dell would like to know what RAID mode we want configured on the SAN for=20 the B80 and 6C4 computers. Sam has told me that, in the Oracle community,=20 mirroring (RAID1) is preferred over RAID 5 for various reasons (RAID5 is:=20 more costly for write-intensive applications, 3 times more likely to incur = data loss, suffers from massive performance degradation during partial=20 outages). RAID1 will be more costly per unit of usable storage. Mirroring=20 seems to be the best choice. Let me know what you think. =20 Here is the Manager's response:=20 =20 Any suggestions on how I can counter points 4 and 5 ? and the last point=20 before his "Thanks" line? Currently we have two B80's (AIX 4.3.3) set up=20 in a HA configuration. They share an external disk array. So if a=20 hardware component in the primary box fails, then it will automatically=20 failover to the secondary box (and at the same time, the secondary box=20 takes control of the external disk array). I think the clustering term in = point (4) is referring to this setup. =20 Thanks for any suggestions. =20 Sam. =20 =20 Sent: November 18, 2003 5:08 PM =20 All the points are valid...however..my thought processes were as follows: =20 1. The System & Core Application disks are resident on the disks within=20 the CPU and Mirrorred (Everyone OK with that I think) =20 2. The Databases are Resident on the SAN =20 3. The SAN disks are RAID 5 as the provide more usable space for the cost = as compared to mirrorring =20 4. As the IBM Systems (B80's & 6C4's) are clusterd thus effectivley=20 Mirrors the RAID 5 Arrays mitigating the issues Sam raises re preformance=20 degradation (which will only ever arise in the event of a failed=20 disk/automated rebuild which is usually configurable to address=20 performance degradation) =20 5. Write to Disk/Commit to Database should be a background process=20 (although I recognise this is a transaction/write intensive based system) =20 This is a standard model that all servers are being deployed with and=20 unless there are any specific technical reasons why this will not work it=20 is the way I would like to see the systems implemented. Remeber, with the = SAN...Reconfiguration of Disks is not a large issue anymore if required in = the future. =20 Although not an AIX/Oracle guy...I disagree with the statement that RAID5=20 is 3 times more susceptable to incur Data Loss. RAID 5 is a proven=20 technology =20 Thanks..... Andrew =20 -----Original Message-----=20 Sent: Tue 18/11/2003 2:56 PM=20 To: Andrew Riem=20 Subject: SAN configuration for Banner =20 Dell would like to know what RAID mode we want configured on the SAN for=20 the B80 and 6C4 computers. Sam has told me that, in the Oracle community,=20 mirroring (RAID1) is preferred over RAID 5 for various reasons (RAID5 is:=20 more costly for write-intensive applications, 3 times more likely to incur = data loss, suffers from massive performance degradation during partial=20 outages). RAID1 will be more costly per unit of usable storage. Mirroring=20 seems to be the best choice. Let me know what you think. =20 Carl=20 Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard --=_alternative 007DFA3388256DE3_= Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Paul, just curious why RAID 01 rathe= r than RAID 10.

RAID 10 is much more resistant to di= sk failures that RAID 01.

10 drives in a RAID 01 with drives h= aving a MTBF of say 100,000 hours.
( don't know if the 100k is low or h= igh )

Each stripe in the RAID 01 has a MTB= F of 20k hours, which is 10k hours
for the array as a whole.

In a RAID 10 each mirrored pair woul= d have an MTBF of 50k hours,
which also appears to give an MTBF o= f 10k hours, but this is where
statistics are misleading.

Lose one drive on each side of the R= AID01 and is down.

The RAID 10 could lose 5 up to drive= s, as long as each failure
is only one side of a mirrored pair,= and still stay up.

Even more beneficial, in the RAID 01= if you lose on drive, you will
lose 50% of read throughput.

Losing a single drive in the RAID 10= will cost you about 10% throughput.

If Matthew Zito is still here, he ca= n no doubt enlighten us with no end of
detail on the subject.

Jared



Paul Drake <discgolfdba@yahoo.= com>
Sent by: ml-errors@fatcity.com

 11/19/2003 12:20 PM
 Please respond to ORACLE-L

       
        To: &nbs= p;      Multiple recipients of list ORACLE-L <ORACLE-L@fa= tcity.com>
        cc: &nbs= p;      
        Subject:=        Re: FW: SAN configuration for Banner


Sam,
 
Dell was perfectly happy to con= figure the following for me on a CX200 unit:
(2 trays of 15 drives, 1 tray 3= 6 GB 15K, 1 tray 73 GB 10K, 1 hot spare per tray)
 
3 x RAID 1 for online redo logs= (members a,b,c, 6 drives total)
2 x RAID 01 for datafiles (8 dr= ives each, 16 drives total)
1 x RAID 1 for archlogs (2 driv= es)
1 x RAID 01 for undo (4 drives)=
 
we used less than half of the a= vailable storage, saving that for when another system is migrated to this u= nit. when creating filesystems, we did not format the entire RAID vols for = live files, and created filesystems for storing local backup sets.
 
You will like having datafiles = on 8 drive RAID 01 (or RAID 10) volumes.
RMAN backups fly like you would= not believe.
 
hth.
 
Paul

Sam Bootsma <sbootsma@gbrownc.on.ca> wrote:
Hi List,
 
We are approaching the cu= sp of a decision on how to store Oracle data files on our SAN.  We don= 't have the SAN yet, but it is due to arrive any week (if not any day). &nb= sp;
 
I passed Cary's "Is RAID = 5 Really a Bargain?" paper to our Sys Admin, which he read and succinctly s= ummarized for the Technical Manager here.  I have also read through a = couple of papers referenced in the BAARF site.  The Sys Admin comments= were:
 
Dell would like to know w= hat RAID mode we want configured on the SAN for the B80 and 6C4 computers. = Sam has told me that, in the Oracle community, mirroring (RAID1) is preferr= ed over RAID 5 for various reasons (RAID5 is: more costly for write-intensi= ve applications, 3 times more likely to incur data loss,  suffers from= massive performance degradation during partial outages). RAID1 will be mor= e costly per unit of usable storage. Mirroring seems to be the best choice.= Let me know what you think.
 
Here is the Manager's res= ponse:  
 
Any suggestions on how I = can counter points 4 and 5 – and the last point before his "Thanks" l= ine?  Currently we have two B80's (AIX 4.3.3) set up in a HA configura= tion.  They share an external disk array.  So if a hardware compo= nent in the primary box fails, then it will automatically failover to the s= econdary box (and at the same time, the secondary box takes control of the = external disk array).  I think the clustering term in point (4) is ref= erring to this setup.
 
Thanks for any suggestion= s.
 
Sam.
 
 
Sent: November 18, 2003 5:08 PM
Subject: RE: SAN configuration for Banner
 
All the points are valid...howe= ver..my thought processes were as follows:
 
1.  The System & Core = Application disks are resident on the disks within the CPU and Mirrorred (E= veryone OK with that I think)
 
2.  The Databases are Resi= dent on the SAN
 
3.  The SAN disks are RAID= 5 as the provide more usable space for the cost as compared to mirrorring<= /font>
 
4.  As the IBM Systems (B8= 0's & 6C4's) are clusterd thus effectivley Mirrors the RAID 5 Arrays mi= tigating the issues Sam raises re preformance degradation (which will only = ever arise in the event of a failed disk/automated rebuild which is usually= configurable to address performance degradation)
 
5.  Write to Disk/Commit t= o Database should be a background process (although I recognise this is a t= ransaction/write intensive based system)
 
This is a standard model that a= ll servers are being deployed with and unless there are any specific techni= cal reasons why this will not work it is the way I would like to see the sy= stems implemented.  Remeber, with the SAN...Reconfiguration of Disks i= s not a large issue anymore if required in the future.
 
Although not an AIX/Oracle guy.= ..I disagree with the statement that RAID5 is 3 times more susceptable to i= ncur Data Loss.  RAID 5 is a proven technology
 
Thanks.....  Andrew
 
-----Original Message----- <= br> From: Carl Nowak
Sent: Tue 18/11/2003 2:56 PM
To: Andrew Riem
Subject: SAN configuration for Banner
 

Dell would like to know what RAID mode we = want configured on the SAN for the B80 and 6C4 computers. Sam has told me t= hat, in the Oracle community, mirroring (RAID1) is preferred over RAID 5 fo= r various reasons (RAID5 is: more costly for write-intensive applications, = 3 times more likely to incur data loss,  suffers from massive performa= nce degradation during partial outages). RAID1 will be more costly per unit= of usable storage. Mirroring seems to be the best choice. Let me know what= you think.
 

Carl

Do you Yahoo!?
Protect your identity with Yahoo! = Mail AddressGuard

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