TDPO and restore speed problem

From: tefetufe . <coskan_at_gmail.com>
Date: Sat, 19 Oct 2013 15:29:36 +0100
Message-ID: <CAGLGTvMiSB4rxZg0Rifu=KKcueppqCfKGc2s1Sozux8U4Pz1kw_at_mail.gmail.com>

Hi,
We are doing some backup restore tests on our brand new environment using tivoli tdpo.
Using rman We are backing up 8TB uncompressed backup in the same campus with 6 channels in 3 hours using 10Gb network and writing into VTL

When we try to restore same backup from another location using 1Gb card with 6 channels and same rman settings we are somehow limited with *16MB /sec *per channel (our previous restores never hit this issue when DB was runnin on solaris and 10G)

No matter how many channels we run total throughput is increasing in linear but per channel limit is still 16MB/sec

I'm kind suspicious about this *16MB/sec *wall we are hitting. As we are not even using whole network bandwidht. I expect we can go higher with less channles but it is not the case. no matter what the number of channels are it is always 16MB/sec
There is no hardware multiplexing
We already tried playin with tcpwindow size on tdpo settings and BACKUP_TAPE_IO_SLAVES=TRUE Database is 11.2.0.3 and using filesystem (veritas with cio) on Redhat 6

 My real wonder is if anybody seen this limitation per channel at all

strace sample outpu

% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------

94.33    0.418938          38     10943      5620 semtimedop
  3.16    0.014031           0     64380           times
  1.44    0.006395           1     10617           semctl
  0.81    0.003601           1      5442           io_submit
  0.26    0.001169           1      1396           io_getevents
  0.00    0.000000           0       168           getrusage


------ ----------- ----------- --------- --------- ----------------

100.00    0.444134                 92946      5620 total

perf sample output is like below.

    56.27%   oracle  oracle              [.] sxorcopychk
    21.92%   oracle  [kernel.kallsyms]   [k] 0xffffffff8103ba4a
     2.29%   oracle  oracle              [.] krbddoh
     1.22%   oracle  oracle              [.] krbr1b1
     0.98%   oracle  oracle              [.] ksfvsubmit
     0.97%   oracle  oracle              [.] ksliwat
     0.91%   oracle  oracle              [.] krbr1b2
     0.89%   oracle  oracle              [.] krbrpr
     0.64%   oracle  oracle              [.] kcbhcvbo
     0.53%   oracle  oracle              [.] krbcdb

Appreciate if anybody hit the same issue before

Regards
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Coskan GUNDOGAR

Email: coskan_at_gmail.com

Blog: http://coskan.wordpress.com
Twitter: http://www.twitter.com/coskan
Linkedin: http://uk.linkedin.com/in/coskan

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http://www.freelists.org/webpage/oracle-l Received on Sat Oct 19 2013 - 16:29:36 CEST