Problem - export over named pipe on Solaris 2.3

We are runnig Oracle 7.0.16.4 on Solaris 2.3 - SUN 1000 and SpacServer 10. We have performance problem with export writing over named pipe to Cybernetics CY-8505 tape drive.

The benchmarks are for 60 MB table.

1. Export to file system:

real	6:11.8
user	6:10.8
sys	  39.0

2. dd this file to tape:

real	2:14.3
user	   8.3
sys	  14.5

3. Write export output over named pipe to dd and the tape:

real	36:25.5
user	 7:16.0
sys	 2:58.1

The problem is with real time beeing so much larger then user slice.

sar -d reports that device with named pipe becomes 80 -90 % busy. Is the named pipe buffered on a disk?

The processes seem to be blocked at the kernel level waiting for I/O. Any ideas what should be changed in the system setup to speed it up? Could we change the buffer size for named pipes?

If I will find a solution I will post it, as it may be usefull for a number of sites.

Thanks,

                                                Edwin Kuprienko

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