ADSM-L

Re: Roll Forward Mode

2001-04-18 08:00:05
Subject: Re: Roll Forward Mode
From: Alan Davenport <alan.davenport AT SELECTIVE DOT COM>
Date: Wed, 18 Apr 2001 07:58:58 -0400
> >From your statistics I see that your log is 2000 MB:
> Log:
>        Available Space (MB): 2,000
>      Assigned Capacity (MB): 2,000
>      Maximum Extension (MB): 0
>      Maximum Reduction (MB): 1,996
>           Page Size (bytes): 4,096
>          Total Usable Pages: 511,488
>                  Used Pages: 279
>                    Pct Util: 0.1
>               Max. Pct Util: 89.3  <--- How??
>
> I'm curious about one thing though.  When in "normal" mode, log consumption
> rarely should exceed about 1%.  Yet your statistics show a max utilization
> of 89.3%.  How did you do that in NORMAL mode?
>
> I operate in roll-forward mode all the time, and the max consumption on my
> log is about 60%.
>
>

Tab, I've noticed my log consumption go way up when there is a lot of
database activity. I am in normal mode. I had to stop doing expiration
processing while the nightly backups from the clients was running
because the log would fill up. What I suspect is going on is that
database update transactions are buffered to the recovery log when they
come in faster than can be processed. My recovery log is normally at
0.1% utilization for a 672 Mb log and a 16 GB database however while
there are a lot of database updates going on I've seen it spike into the
low to mid 20's.

                   Al
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