<div class="socmaildefaultfont" dir="ltr" style="font-family:Arial, Helvetica, sans-serif;font-size:10.5pt" ><div dir="ltr" ><p style="margin: 5px 0px 0px; color: rgb(34, 34, 34); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 12px;" >When an AFM gateway is flushing data to the target (home) it starts flushing with a few threads (Don't remember the number) and ramps up to afmNumFlushThreads. How quickly this ramp up occurs is controlled by afmFlushThreadDealy. The default is 5 seconds. So flushing only adds threads once every 5 seconds. </p>
<p style="margin: 5px 0px 0px; color: rgb(34, 34, 34); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 12px;" >This was an experimental parameter so your milage may vary.</p></div>
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<div dir="ltr" >Scott Fadden<br>Spectrum Scale - Technical Marketing<br>Phone: (503) 880-5833<br>sfadden@us.ibm.com<br>http://www.ibm.com/systems/storage/spectrum/scale</div>
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<blockquote data-history-content-modified="1" dir="ltr" style="border-left:solid #aaaaaa 2px; margin-left:5px; padding-left:5px; direction:ltr; margin-right:0px" >----- Original message -----<br>From: "Billich Heinrich Rainer (PSI)" <heiner.billich@psi.ch><br>Sent by: gpfsug-discuss-bounces@spectrumscale.org<br>To: "gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>Cc:<br>Subject: [gpfsug-discuss] AFM: Slow startup of flush from cache to home<br>Date: Fri, Oct 13, 2017 10:16 AM<br>
<div><font face="Default Monospace,Courier New,Courier,monospace" size="2" >Hello,<br><br><br><br>Running an AFM IW cache we noticed that AFM starts the flushing of data from cache to home rather slow, say at 20MB/s, and only slowly increases to several 100MB/s after a few minutes. As soon as the pending queue gets no longer filled the data rate drops, again.<br><br><br><br>I assume that this is a good behavior for WAN traffic where you don’t want to use the full bandwidth from the beginning but only if really needed. For our local setup with dedicated links I would prefer a much more aggressive behavior to get data transferred asap to home.<br><br><br><br>Am I right, does AFM implement such a ‘slow startup’, and is there a way to change this behavior? We did increase afmNumFlushThreads to 128. Currently we measure with many small files (1MB). For large files the behavior is different, we get a stable data rate from the beginning, but I did not yet try with a continuous write on the cache to see whether I see an increase after a while, too.<br><br><br><br>Thank you,<br><br><br><br>Heiner Billich<br><br><br><br>--<br><br>Paul Scherrer Institut<br><br>Science IT<br><br>Heiner Billich<br><br>WHGA 106<br><br>CH 5232 Villigen PSI<br><br>056 310 36 02<br><br><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__www.psi.ch&d=DwIGaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=WDtkF9zLTGGYqFnVnJ3rywZM6KHROA4FpMYi6cUkkKY&m=oOrvSj2SQ96R2IlqeBCAr1a4P1iiAoH7ltrylfmBltA&s=M22skyIzFv0EAU9eWqhcbEC0vvlhTAe-dcIDMfnOK9Q&e=" target="_blank" >https://urldefense.proofpoint.com/v2/url?u=https-3A__www.psi.ch&d=DwIGaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=WDtkF9zLTGGYqFnVnJ3rywZM6KHROA4FpMYi6cUkkKY&m=oOrvSj2SQ96R2IlqeBCAr1a4P1iiAoH7ltrylfmBltA&s=M22skyIzFv0EAU9eWqhcbEC0vvlhTAe-dcIDMfnOK9Q&e=</a><br><br> <br><br> <br><br><br><br>_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at spectrumscale.org<br><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__gpfsug.org_mailman_listinfo_gpfsug-2Ddiscuss&d=DwIGaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=WDtkF9zLTGGYqFnVnJ3rywZM6KHROA4FpMYi6cUkkKY&m=oOrvSj2SQ96R2IlqeBCAr1a4P1iiAoH7ltrylfmBltA&s=25M9gkJOC6oIe9SeyMwKvS-i4UDPKmf7EOX6ngzk5n4&e=" target="_blank" >https://urldefense.proofpoint.com/v2/url?u=http-3A__gpfsug.org_mailman_listinfo_gpfsug-2Ddiscuss&d=DwIGaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=WDtkF9zLTGGYqFnVnJ3rywZM6KHROA4FpMYi6cUkkKY&m=oOrvSj2SQ96R2IlqeBCAr1a4P1iiAoH7ltrylfmBltA&s=25M9gkJOC6oIe9SeyMwKvS-i4UDPKmf7EOX6ngzk5n4&e=</a></font><br> </div></blockquote>
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