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Assist with ASM config for greater then 10TB instance [message #647301] Mon, 25 January 2016 21:49 Go to next message
oracledba88
Messages: 5
Registered: January 2016
Junior Member
- followed: Deployment of very large databases (10TB to PB range) with Automatic Storage Management (ASM) (Doc ID 368055.1)
- on 12c instance, ASM, OVM ...
- multiple issues:
a) only 50% of of the available underlying disk was able to be used for tablespace create (will upload details) ----- ?? how can use use all disk
b) doing RMAN perf test ... not as fast as we need for FULL's ... how to we maximize performance

- need best practice direction
_______________________________________________________________________________________________________________________________
we know we have a 4 to 10+ TB application coming under support .... (this is significantly larger then what we've supported to date). We are working on a POC to understand best configuration possible to support this size.

the focus is can we back this up? So this is how do we build a huge environment ..... and then do successful RMAN full backups within a reasonable time period. (we know we'll gain benefit from block-change tracking for the incremental backup ...).

our issue is "reads" from ASM. This is not a "write" problem. Estimate 85% of our elapsed time is the "read" process.

How we have gained performance so far:

- increase allocation_unit_size (from original: 1mb, to tries at 4mb and 16mb)
- we have also looked at stripe size, and template change (from Fine -> Course).

we need direction on best practice on setup for ASM.
looking forward to your assistance
_____________________________________________________________________________________________________________

i ran into this (only 50% of available disk was able to be allocated to tablespace) . -- please help me understand why i could not use all available disk
SQL>  create tablespace soe3 datafile '+DATA3';
create tablespace soe3 datafile '+DATA3'
*
ERROR at line 1:
ORA-01119: error in creating database file '+DATA3'
ORA-17502: ksfdcre:4 Failed to create file +DATA3
ORA-15041: diskgroup "DATA3" space exhausted

Looking as ASM,  we see space consumed:

SQL> select name, total_mb, free_mb from v$asm_diskgroup;

NAME                             TOTAL_MB    FREE_MB
------------------------------ ---------- ----------
DATA2                              102396     101828
DATA3                               98256        208
DATA                               102399     102337

____________________________________________________________________________________
so how to we best configure ASM , create the storage , so that we utilize all disk available at maximium performance

thanks all for the help

[Updated on: Tue, 26 January 2016 03:34] by Moderator

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Re: Assist with ASM config for greater then 10TB instance [message #647302 is a reply to message #647301] Tue, 26 January 2016 01:57 Go to previous messageGo to next message
John Watson
Messages: 7148
Registered: January 2010
Location: Global Village
Senior Member
Welcome to the forum. Please read our OraFAQ Forum Guide and How to use [code] tags and make your code easier to read

First, the note you reference is for release 10.2.x, it has no relevance for 12.x. Following it would be insane in the current release.
Second, you say that you changed templates from fine to coarse striping. Really? In 12.x, only one template is fine striped. When you looked at the file type for which it is used, why did you want to change it?
Third, your DATA3 diskgroup has hardly any free space. It is not surprising that you cannot create anything on it. Specially when you consider redundancy. What redundancy levels are you using?
Fourth, your POC is for a 10TB database, but your diskgroups are only 100GB. I don't understand this.

Overall, I find it hard to understand what you have done, and what problems you are facing. Perhaps you could begin with a description of the environment?
Re: Assist with ASM config for greater then 10TB instance [message #647305 is a reply to message #647302] Tue, 26 January 2016 03:51 Go to previous messageGo to next message
Mahesh Rajendran
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Registered: March 2002
Location: oracleDocoVille
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Account Moderator
+1 to John. Got nothing more to say.
Assuming OMF default datafile is still 100m in 12c, depending on redundancy, it is expected to fail.
DATA3 is exhausted. Just use others.

[Updated on: Tue, 26 January 2016 03:51]

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Re: Assist with ASM config for greater then 10TB instance [message #647336 is a reply to message #647305] Tue, 26 January 2016 15:02 Go to previous messageGo to next message
oracledba88
Messages: 5
Registered: January 2016
Junior Member
Yes, def do need help

we have been only given a small POC to create a test ... and will then have to try and extrapolate up. if we can backup 100gb in 10 minutes, then we estimate that if our database size is 1000gb the our estimate backup time is 100 minutes.

that said ---- if we are to build and environment with expectatoin of 10TB of data .... how do we configure for best success
a) size of disk and number of disks in diskgroup
b) allocation unit_size
c) stripping

looking for best practices for configuring ASM (and diskgroup) .... our latest try was DATA3 (16mb au_size, 1mb stripe, template to 'fine'). our original was DATA (1mb au_size, defaults for all other parameters0.

and looking at DATA3 ...how can we understand why only 50% was able to be allocated to tablespace?

and finally, the 10g document was only document i found on MOS. is there a 12c document / best practice for defining storage for expected very large data volumes.

thank you
Re: Assist with ASM config for greater then 10TB instance [message #647341 is a reply to message #647336] Tue, 26 January 2016 18:00 Go to previous messageGo to next message
BlackSwan
Messages: 25716
Registered: January 2009
Location: SoCal
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https://docs.oracle.com/database/121/nav/portal_booklist.htm
Re: Assist with ASM config for greater then 10TB instance [message #647351 is a reply to message #647336] Wed, 27 January 2016 01:11 Go to previous message
John Watson
Messages: 7148
Registered: January 2010
Location: Global Village
Senior Member
I shall not answer this,Quote:
how can we understand why only 50% was able to be allocated to tablespace?
because the answer is so trivial that your first glance at the syntax of CREATE DISKGROUP wil tell you the answer. Specially as Mahesh and I have already told you.

As for the AU size, how did you change it? Did you really set that _underscore parameter? What is "stripe" in this context, and how did you change it? How did you change he template?

Backup performance: how are you measuring it? How are you backing up? What is your hardware? How are you simulating this 10TB SAN? How are the LUNs configured (if you are using LUNs)?

IF you want to take this project seriously, you do need to read the ASM docs or attend Oracle Uni's introductory course on RAC and GI. What training have they given you so far?
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