I've run database queries that timestamped the file retrieval and as it
seems, AdvFS is not a problem in this case. I also ran a "find . -exec
time sum {} \;" and got excellent response times. It seems, the problem is
somewhere else, in Oracle or network.
Many thanks to Dr. Thomas.Blinn, Udo de Boer, Lyndon Handy and Nemholt,
Jesper Frank. I've included some general information from replies that may
be of interest to those trying to resolve a similar issue.
>3 very important parameters to look at when tuning a very high performance
>Oracle database on TRU64 Unix (I tuned them for years).
>
>1) db_file_multiblock_read! Check this and set it properly to manage the
>32k chunk sizes you mentioned. TRU63 unix handles 128K per I/O max size,
>you 32k x db_file_multiblock_read should = 128K exactly if properly tuned
>
>2) check you Oracle database logs to determine if/when checkpoints are
>happening. Do they correlate?
>
>3) Monitor the memory and ubc system metrics carefully with vmubc and pay
>careful attention to the file system cache size for UBC. You may have to
>reduce ubc_max_percent dramatically on a large-memory system to ensure there
>sufficient free memory on the system, ~ 2 or 3% value on an 8GB system, less
>if using raw partitions. Adjust the other corresponding ubc parameters
>accordingly
>How are the files organized ? (many files in a few directories or few files
>in many directories)
>
>Try running Collect (/usr/sbin/collect) with a frequency of 10 seconds
>during a period where you have the problem.
>Afterwards you can see in the Collect data if anything special (memory,
>disk, cpu) happened in that period.
>
>Be sure to get the latest Collect. The one present by default on a 5.1 PK3
>has a bug related to the memory statistics.
Thanks
Alex Gorbachev
>Managers,
>
>I am trying to pinpoint a source of intermittent slowdowns on a 300 GB AdvFS
>domain with over a million files - GS160/Tru64 5.1 PK3. Overall performance
>is good but every once in a while a file takes a long time to retrieve (from
>30 seconds to 10 minutes).
>
>Any insight on troubleshooting/tuning?
>
>Thank you,
>Alex Gorbachev
Received on Fri Nov 09 2001 - 03:40:44 NZDT