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From 4233fe30b315737ac8c4d857e2b04e021c2e2886 Mon Sep 17 00:00:00 2001
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From: Pavel Cahyna <pcahyna@redhat.com>
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Date: Mon, 16 Aug 2021 10:10:38 +0300
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Subject: [PATCH] Revert the main part of PR #2299
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multipath -l is very slow with many multipath devices. As it will be
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called for every multipath device, it leads to quadratic time complexity
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in the number of multipath devices. For thousands of devices, ReaR can
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take hours to scan and exclude them. We therefore have to comment
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multipath -l out, as it is a huge performance regression, and find
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another solution to bug #2298.
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---
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usr/share/rear/lib/layout-functions.sh | 5 ++++-
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1 file changed, 4 insertions(+), 1 deletion(-)
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diff --git a/usr/share/rear/lib/layout-functions.sh b/usr/share/rear/lib/layout-functions.sh
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index cdd81a14..8c8be74b 100644
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--- a/usr/share/rear/lib/layout-functions.sh
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+++ b/usr/share/rear/lib/layout-functions.sh
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@@ -771,7 +771,10 @@ function is_multipath_path {
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# so that no "multipath -l" output could clutter the log (the "multipath -l" output is irrelevant here)
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# in contrast to e.g. test "$( multipath -l )" that would falsely succeed with blank output
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# and the output would appear in the log in 'set -x' debugscript mode:
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- multipath -l | grep -q '[[:alnum:]]' || return 1
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+ #
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+ # Unfortunately, multipat -l is quite slow with many multipath devices
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+ # and becomes a performance bottleneck, so we must comment it out for now.
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+ #multipath -l | grep -q '[[:alnum:]]' || return 1
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# Check if a block device should be a path in a multipath device:
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multipath -c /dev/$1 &>/dev/null
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}
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--
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2.26.3
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