John
You are correct, the effect on smaller databases is minimal. My tests were
done on a 17+GB database with many containers of differring extent sizes.
Other parms you should be aware of is the parallelism setting. For backup
this will assign a thread(or process on UNIX) to a tablespace, thus you can
backup multiple table spaces in parallel. The key here is to ensure you
have a sufficient # of buffers available.
Here are some basic guidelines for backup performance
# of buffers = max(2x# targets, parallelism+# targets+2)
buffersize = Multiple of your largest extentsize +1
Parallelism = min(# of processors +1,# of tablespaces)
These are just guidelines, each individual's results may vary depending on
the hardware/storage/network/device configuration.
Hope this helps.
_____________________________________________
Dale M. McInnis IBM Toronto Lab
Senior Technical Manager, DB2 UDB Backup, Data Protection and Recovery
Email: [EMAIL PROTECTED]
Phone: (905) 413-2397, Fax: (905) 413-4849, T/L: 969-2397
"John Lantz"
<john.lantz@zuric
hna.com> To
Sent by: [EMAIL PROTECTED]
owner-db2eug@Lugw cc
ash.org
Subject
Re: [DB2EUG] Quantifying the
01/17/2003 01:15 savings of BACKUP DB with 129-page
PM buffers
Please respond to
"John Lantz"
<john.lantz@zuric
hna.com>
After I saw his comments yesterday, I played around backing up a tablespace
last night. Here are my statistics:
- tablespace has an extent size of 32
- it's just over 1 gb of allocated space
When backing up the tablespace:
- with no "buffer size " parm, it took 836mb (using the default of 1024)
- with a "buffer size 33", it took 854mb
- with a "buffer size 129" , it also took 836mb
You can clearly see that specifying a buffersize that is too small, it
required more space. But whether I specified 129 or took the default of
1024, it didn't seem to make any difference. Maybe I would see a
difference on a bigger database. Obviously, your results may vary....
Thanks.
[EMAIL PROTECTED]@Lugwash.org on 01/17/2003 12:37:16 PM
Please respond to [EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
cc:
Subject: [DB2EUG] Quantifying the savings of BACKUP DB with 129-page
buffers
Hello,
I'm very glad to see heavy-hitters like Mr. McInnis providing valuable,
detailed information about such an integral part of my job as a DB2 DBA.
His response to a recent inquiry regarding shrinking backup size was to
reduce the backup buffer size from its default of 1024 to a mere 129 pages,
which I understand to be the size of four 32-page extents (with an extra
page added on for management overhead). Is the amount of disk space saved
proportional to the number of tablespaces being backed up?
Thanks in advance,
Fred Sobotka
Database Administrator
IBM Certified Solutions Expert - DB2 UDB V7.1 Administration for Unix,
Windows, and OS/2
CollegeNET, Inc.
-
::: When replying to the list, please use 'Reply-All' and make sure
::: a copy goes to the list ([EMAIL PROTECTED]).
*** To unsubscribe, send 'unsubscribe' to [EMAIL PROTECTED]
*** For more information, check http://www.db2eug.uni.cc
******************* PLEASE NOTE *******************
This E-Mail/telefax message and any documents accompanying this
transmission may contain privileged and/or confidential information and is
intended solely for the addressee(s) named above. If you are not the
intended addressee/recipient, you are hereby notified that any use of,
disclosure, copying, distribution, or reliance on the contents of this
E-Mail/telefax information is strictly prohibited and may result in legal
action against you. Please reply to the sender advising of the error in
transmission and immediately delete/destroy the message and any
accompanying documents. Thank you.
-
::: When replying to the list, please use 'Reply-All' and make sure
::: a copy goes to the list ([EMAIL PROTECTED]).
*** To unsubscribe, send 'unsubscribe' to [EMAIL PROTECTED]
*** For more information, check http://www.db2eug.uni.cc
-
::: When replying to the list, please use 'Reply-All' and make sure
::: a copy goes to the list ([EMAIL PROTECTED]).
*** To unsubscribe, send 'unsubscribe' to [EMAIL PROTECTED]
*** For more information, check http://www.db2eug.uni.cc
