Hi Amir Are you seeing a performance problem (complaints from dba's/users) or are the "b" field from iostat just bothering you?
I would recommend you read "Solaris Performance and Tools: DTrace and MDB Techniques" It's written for Solaris 10 / Opensolaris, but lots of the info and concepts is applicable to Solaris 9. (Chapters 4 and 5) On 5/18/07, Amir Hameed <[EMAIL PROTECTED]> wrote:
Folks, I just joined this forum and this is my first ever post. I am doing a performance analysis of our mission critical application. Below is the salient configuration information: - OS is Solaris9 - Server is a SunFire 20k domain with 20 dual-core SPARCIV+ processors - Storage is EMC's DMX-3000 - The server has four HBAs using DMP for multi-pathing - Veritas VM 4.1 - This is an Oracle 11.5.9/9.2.0.6 (64-bit) application and the database size is 1.5 TB. The databases is using Oracle's ODM (Oracle disk manager) interface for I/Os. The application is hybrid in nature with mostly batch and does a lot of I/Os As part of statistics gathering, I collected stats from iostat, vmstat and sar at two-seconds interval. The analysis of the asvc_t and wsvc_t statistics from iostat shows that approximately over 95% of the I/O had the average response time (asvc_t+wsvc_t) of around 10 ms or less. This looks quite good to me. However, at the same time, vmstat's "b" column consistently shows numbers that average around 12 but fluctuate into 30s sometime. This is where I am having a hard time understanding it, that is, iostat looks good but vmstat is reporting blocked I/O threads. Can someone please explain what should be primarily looked at when analyzing I/Os on a system; I am thinking that iostat is the tool to consult. But then what is the significance of the "b" column in vmstat and how much should one worry about this value. I would like to point here that the "r" column from vmstat and "runq-sz" from sar mostly have "0" values and the CPU usage (usr+sys) is also not too high. Any help will be appreciated Thanks This message posted from opensolaris.org _______________________________________________ perf-discuss mailing list perf-discuss@opensolaris.org
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