<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Jul 24, 2018 at 8:35 PM, Raghavendra Gowdappa <span dir="ltr"><<a href="mailto:rgowdapp@redhat.com" target="_blank">rgowdapp@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote"><span class="">On Tue, Jul 24, 2018 at 6:30 PM, Ravishankar N <span dir="ltr"><<a href="mailto:ravishankar@redhat.com" target="_blank">ravishankar@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div class="m_5808951623070163661m_-1358384196294352466moz-cite-prefix">On 07/24/2018 02:56 PM, Raghavendra
Gowdappa wrote:<br>
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<div>All,<br>
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I was trying to debug regression failures on [1] and observed
that split-brain-resolution.t was failing consistently.<br>
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TEST 45 (line 88): 0 get_pending_heal_count patchy<br>
./tests/basic/afr/split-brain-<wbr>resolution.t .. 45/45 RESULT
45: 1<br>
./tests/basic/afr/split-brain-<wbr>resolution.t .. Failed 17/45
subtests <br>
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Test Summary Report<br>
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./tests/basic/afr/split-brain-<wbr>resolution.t (Wstat: 0
Tests: 45 Failed: 17)<br>
Failed tests: 24-26, 28-36, 41-45<br>
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<div>On probing deeper, I observed a curious fact - on most
of the failures stat was not served from md-cache, but
instead was wound down to afr which failed stat with EIO
as the file was in split brain. So, I did another test:</div>
<div>* disabled md-cache</div>
<div>* mount glusterfs with attribute-timeout 0 and
entry-timeout 0</div>
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<div>Now the test fails always. So, I think the test relied
on stat requests being absorbed either by kernel attribute
cache or md-cache. When its not happening stats are
reaching afr and resulting in failures of cmds like
getfattr etc. </div>
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This indeed seems to be the case. Is there any way we can avoid the
stat? When a getfattr is performed on the mount, aren't lookup +
getfattr are the only fops that need to be hit in gluster? <br></div></blockquote><div><br></div></span><div>Its a black box to me how kernel decides whether to do lookup or stat. But I guess, if only stat is needed and its not available in cache it would do a stat.</div></div></div></div></blockquote><div><br></div><div>Another thing you can do is mounting with a higher value of attribute-timeout. Let us know whether it works.</div><div> <br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span class=""><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div text="#000000" bgcolor="#FFFFFF">
-Ravi<br>
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<div>Thoughts?<br>
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<div>[1] <a href="https://review.gluster.org/#/c/20549/" target="_blank">https://review.gluster.org/#/c<wbr>/20549/</a><br>
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