Re: Performance problems after moving to new hardware
- From: Wayne Smith <wts@xxxxxxxxx>
- To: sbecker6925@xxxxxxxxx
- Date: Thu, 5 Mar 2015 13:02:18 -0500
Sorry if I missed another suggestion of this in this thread, but ...
11.2.0.2 is notorious for a system stats bug where SREADTIM and MREADTIM
are 10,000 times larger than they should be. Once broken, you can
manually (using DBMS_STATS.SET_SYSTEM_STATS ) set these values to more
sane value
s
(10,000 times smaller) to avoid the terrible performance that can occur.
See doc 9842771.8.
Cheers, Wayne
On Thu, Mar 5, 2015 at 10:11 AM, Sandra Becker <sbecker6925@xxxxxxxxx>
wrote:
> Correct, the new server waits significantly longer than the old server. I
> have a ticket open with Oracle support. At this point, we're leaning
> towards the server configuration rather than the storage. We migrated our
> lower environment databases to the same type of server and simply detached
> the storage from the old server and attached it to the new server. They are
> seeing the same problem in the lower environments.
>
> Since we have moved several production databases to the new hardware, I
> want to run a few AWR reports on the other databases migrated to this
> server to see what the waits are, regardless of the fact no one is
> reporting issues with any other database.
>
> Sandy
>
> On Thu, Mar 5, 2015 at 1:30 AM, Iliya Peregoudov <iperegudov@xxxxxxxx>
> wrote:
>
>> I think I correctly decrypted AWR stats.
>>
>> AWR from old server
>>
>> Host CPU (CPUs: 32 Cores: 16 Sockets: 4)
>>
>> Event Waits Time(s) Avg wait (ms) % DB time Wait
>> Class
>> ----------------------- ------- ------- ------------- ---------
>> ----------
>> db file parallel read 72,570 4,355 60 50.98 User
>> I/O
>> DB CPU 2,092 24.49
>> db file sequential read 387,105 1,308 3 15.31 User
>> I/O
>> direct path write temp 3,227 509 158 5.96 User
>> I/O
>> db file scattered read 133,051 236 2 2.27 User
>> I/O
>>
>> Snap Time Load %busy %user %sys %idle %iowait
>> --------------- ----- ----- ----- ----- ----- -------
>> 24-Feb 10:00:42 1.06
>> 24-Feb 11:00:59 2.02 4.40 1.74 2.66 95.60 0.00
>>
>> AWR from new server
>>
>> Host CPU (CPUs: 32 Cores: 4 Sockets: 1)
>>
>> Event Waits Time(s) Avg wait (ms) % DB time Wait
>> Class
>> ----------------------- ------- ------- ------------- ---------
>> ----------
>> db file parallel read 46,337 18,808 406 43.47 User
>> I/O
>> db file sequential read 154,062 6,861 45 15.86 User
>> I/O
>> direct path write temp 8,394 3,203 382 7.40 User
>> I/O
>> log file sync 3,002 1,564 521 3.61
>> Commit
>> DB CPU 1,433 3.31
>>
>> Snap Time Load %busy %user %sys %idle %iowait
>> --------------- ----- ----- ----- ----- ----- -------
>> 03-Mar 10:00:42 2.73
>> 03-Mar 11:00:37 2.95 7.12 4.69 2.43 92.88 0.00
>>
>>
>> New server waits for I/O much more per hour (30k seconds vs 6k seconds).
>> Average read waits are also 10 times larger on new server (406ms vs 60ms,
>> 45ms vs 3ms). CPU on new server is under-loaded I think because of waits.
>> It seems that old server was better balanced in IO/CPU throughput.
>>
>>
>> On 04.03.2015 18:48, Ls Cheng wrote:
>>
>>> I cant read anything useful, cant you format the output or paste a
>>> screenshot :-?
>>>
>>
>>
>> --
>> //www.freelists.org/webpage/oracle-l
>>
>>
>>
>
>
> --
> Sandy
> GHX
>
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