This was a surprise?Quote:
Originally posted by newbie
This shows that Oracle performance is caused by slow disk I/O (Oracle spends alot of time waiting).
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This was a surprise?Quote:
Originally posted by newbie
This shows that Oracle performance is caused by slow disk I/O (Oracle spends alot of time waiting).
Well they got the proof that i/o is the bottle neck what makes them that i/o is not the cause? Ask them to state the fact, writtenQuote:
Originally posted by newbie
Unix guys in our company don't think this is the case. Maybe we need to tune a kernel parameter as well. Can you please advise? Thanks
Before you change any parameter, first do some disk tests to know about the disk throughput ( I would say stress test on the disk system). Use dd command.
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set maxpgio=1024
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I think maxpgio is set very low. Change this to 65536.
And run the test. Also during the import, collect system wise statistics using vmstat, iostat, sar etc.
Tamil
I did some research online and found several cases people complain about the internal FibreChannel disk in Sunfire v880. Many seem to point out that the internal FC disks perform well w/o Oracle but as soon as you put Oracle on it..it just crawling...your thoughts?? Thanks
We use Sunfire with EMC disk array. No problem so far.
In general, EMC disk array is superior than Sun's Disk Array in all aspects.
Did you do dd testing?
Tamil
Hi Tamil & everyone, thank you so much for helping me for the last few days, well we just got the official words from Sun; the v880 internal disks are not suitable for Oracle databases due to lack of io caching(it doesn't have one). They recommended to us to hook up the Sunfire v880 box to an external disk array. Thanks
Hi,
we have exctly the same problem with a V280 and oracle installed on internal fibre channel disks. Is there an official statement from sun on the website somewhere or did you got this information by mail/phone?
Why a bug?Quote:
Originally posted by tamilselvan
I think the *.filesystemio_options='ASYNCH' may be wrong. It seems to be a bug in oracle 9i.
Why not set filesystemio_options=directio. This will enable direct I/O.
BTW, filesystemio_options=none is the default for AIX.
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Why a bug?
Why not set filesystemio_options=directio. This will enable direct I/O.
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8 months ago, after we built the IBM p690 server with EMC DMX disk array 2000, I was testing the server. W/o async IO, Oracle cannot be installed on IBM AIX 5.2. I played around the parameter filesystem_options. Since, async IO is enabled on the server, I set this parameter to ASYNC. To my surprise, the system's performance nose dived. When I set it to NONE, I got better performance. This test was conducted on pre-prod env where raw devices are used.
On the JFS, I did the same test with ASYNC value, again the perf went down. But I did not do the test with directio option. I can do it today and post the result.
Tamil
I did a test on JFS with filesystemio_options=directio. The perf is same. No diff at all.
Tamil