Buffer Free Pages

deldrumdeldrum Posts: 4
edited March 31, 2015 4:23AM in SQL Monitor Previous Versions
Hi,
I've recently started using SQL Monitor and am a bit confused by the Buffer Free Pages metric. We occasionally get performance issues on our low usage website (SQL Server 2008 R2 Standard) and there appears to be a correlation between the performance issues and the Buffer Free Pages value. However, as far as I can tell, the performance is bad when BFP is high (above say 10,000). Can anyone explain what I am seeing and/or point me at a different metric to monitor that would be more useful? At the moment I'm assuming that the rise in BFP (which I would otherwise expect to be a good thing) is actually a symptom of a problem elsewhere but I'm not sure where to look.
Thanks
BufferFreePages.png

Comments

  • Hi Deldrum,

    The "Buffer free pages" metric is just the total number of free pages available in the buffer pool. At the bottom of the description given for the metric it also suggests to check the Buffer cache hit ratio and gives some values for that as well. The Buffer Cache hit ratio indicates how frequently a query gets information from cache instead of accessing the hard disk (see also the description for this metric in SQL Monitor for guideline values).

    I also read that Buffer page life expectancy is useful as well; a high buffer page life expectancy indicates that buffer pages are being reused often, which in turn indicates that the SQL Server is not under any memory pressure.

    I hope this helps!

    Kind regards,
    Alex
    Product Support Engineer | Redgate Software

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