[Veritas-bu] NBU Data Buffer sizes

Perfect is an absolute...unfortunately in tuning there 
are no absolutes ;-)

Are you multiplexing?
What tape device are you using?
What's the IO to the tape device?
What's your network speed?


Quoting Tim Allen <tallen201 AT hotmail DOT com>:

> 
> It doesn't wait for a full buffer quite as often as 
it waits for an empty
> buffer though.
>
> Example:
> ...
> waited for empty buffer 462164 times, delayed 466388 
times, read 40990432
> Kbytes
> ...
> waited for full buffer 1100 times, delayed 12622 times
> ...
>
> So in this case, wouldn't growing the buffer or 
number of buffers possibly
> help?  Waiting for empty buffer would mean there is 
more data coming from
> the network than the drive(s) can handle.
>
> If everything is working perfectly, would the bptm 
logs contain no entries
> for "waited for full" or "waited for empty" buffer?
>
>
>
>
> >From: "David A. Chapa" <david AT xbpadm-commands DOT com>
> >Reply-To: "David A. Chapa" <david@xbpadm-
commands.com>
> >To: Tim Allen <tallen201 AT hotmail DOT com>
> >CC: Veritas-bu AT mailman.eng.auburn DOT edu
> >Subject: Re: [Veritas-bu] NBU Data Buffer sizes
> >Date: Mon, 7 May 2001 09:05:25 -0700 (PDT)
> >
> >At first glance, it doesn't look like you should grow
> >the data buffers, but look at your network.  Wait for
> >Full buffer means it is waiting on the network...I'd
> >check there first.
> >
> >
> >
> >Quoting Tim Allen <tallen201 AT hotmail DOT com>:
> >
> > > Hello.
> > >
> > > A database backup is taking a bit longer than
> >expected, and I was
> > > considering bumping up the data buffers.
> > > SIZE_DATA_BUFFERS is currently 64512 and
> >NUMBER_DATA_BUFFERS is 16.
> > >
> > > The bptm log has the following entries;
> > >
> > > 04:12:47 [12400] <2> fill_buffer: [12399] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 462164 times, delayed 466388 times, read 
40990432
> >Kbytes
> > > 04:12:47 [12399] <2> write_data: waited for full
> >buffer 1100 times, delayed
> > >
> > > 1262
> > > 2 times
> > > 04:29:51 [12433] <2> fill_buffer: [12432] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 492546 times, delayed 498792 times, read 
43451936
> >Kbytes
> > > 04:29:51 [12432] <2> write_data: waited for full
> >buffer 1206 times, delayed
> > >
> > > 1131
> > > 1 times
> > > 06:52:49 [13024] <2> fill_buffer: [13023] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 426891 times, delayed 430477 times, read 
37139232
> >Kbytes
> > > 06:52:49 [13023] <2> write_data: waited for full
> >buffer 591 times, delayed
> > > 10367
> > > times
> > > 07:45:18 [13096] <2> fill_buffer: [13095] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 543885 times, delayed 549783 times, read 
47816800
> >Kbytes
> > > 07:45:18 [13095] <2> write_data: waited for full
> >buffer 930 times, delayed
> > > 5408
> > > times
> > > 08:13:28 [13810] <2> fill_buffer: [13808] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 38963 times, delayed 103462 times, read 
2457696
> >Kbytes
> > > 08:13:29 [13808] <2> write_data: waited for full
> >buffer 0 times, delayed 0
> > > times
> > > 08:48:43 [14012] <2> fill_buffer: [14011] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 38882 times, delayed 103166 times, read 
2457696
> >Kbytes
> > > 08:48:44 [14011] <2> write_data: waited for full
> >buffer 0 times, delayed 0
> > > times
> > > 09:23:17 [14150] <2> fill_buffer: [14149] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 37823 times, delayed 100564 times, read 
2386784
> >Kbytes
> > > 09:23:18 [14149] <2> write_data: waited for full
> >buffer 0 times, delayed 0
> > > times
> > > 09:54:18 [14302] <2> fill_buffer: [14301] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 34057 times, delayed 90351 times, read 2150432
> >Kbytes
> > > 09:54:19 [14301] <2> write_data: waited for full
> >buffer 3 times, delayed 32
> > >
> > > time
> > > s
> > > 10:05:10 [13608] <2> fill_buffer: [13607] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 550854 times, delayed 557508 times, read 
46860128
> >Kbytes
> > > 10:05:10 [13607] <2> write_data: waited for full
> >buffer 85 times, delayed
> > > 2284 t
> > > imes
> > > 10:18:30 [13885] <2> fill_buffer: [13884] socket 
is
> >closed, waited for
> > > empty
> > > buf
> > > fer 421021 times, delayed 424891 times, read 
39006624
> >Kbytes
> > > 10:18:30 [13884] <2> write_data: waited for full
> >buffer 597 times, delayed
> > > 3158
> > >
> > >
> > > There are more delays waiting for an empty buffer
> >than a full buffer so I
> > > was considering bumping the SIZE_DATA_BUFFERS to
> >129024.
> > >
> > > Hmmm...  I guess the only reason for sending this 
e-
> >mail was to ask if this
> > >
> > > sounds reasonable for what is in the bptm logs?
> > >
> > > I'll have to try it and find out if this improves
> >anything next time.
> > >
> > >
> > > Tim Allen
> > >
> > >
> > >
> 
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> > >
> >
> >
> >
> ><><><><><><><><><><><><><><><><><><><><>
> >David A. Chapa
> >Consulting Manager
> >DataStaff, Inc.
> >847 413 1144
> >http://www.consulting.datastaff.com
> >---------------------------------------
> >http://www.xbpadm-commands.com
> >NBU-LSERV AT datastaff DOT com - Adv. Scripting
>
> 
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<><><><><><><><><><><><><><><><><><><><>
David A. Chapa
Consulting Manager
DataStaff, Inc.
847 413 1144
http://www.consulting.datastaff.com
---------------------------------------
http://www.xbpadm-commands.com
NBU-LSERV AT datastaff DOT com - Adv. Scripting