37 lines
1.3 KiB
Diff
37 lines
1.3 KiB
Diff
From 3e8ae32c961f0a3a6ba32881e88a49d5cbf656cd Mon Sep 17 00:00:00 2001
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From: Jeff Mahoney <jeffm@suse.com>
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Date: Fri, 11 Jan 2019 09:57:48 -0500
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Subject: README: document impact of balance + quota groups
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References: fate#325529 jsc#SLE-3188
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The combination of balance and quota groups as the number of references
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to extents rises (either via snapshots, dedupe, or reflink copies) can
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be extreme.
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The file system performs quota group accounting for every extent relocated
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and the result can be the appearance of stalled system as the
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transaction commit can take a very long time.
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Signed-off-by: Jeff Mahoney <jeffm@suse.com>
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---
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README.md | 4 ++++
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1 file changed, 4 insertions(+)
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diff --git a/README.md b/README.md
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index 07a8104..d59f3d6 100644
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--- a/README.md
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+++ b/README.md
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@@ -66,6 +66,10 @@ the same set of blocks is affected.
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The balance command uses filters to do the work in smaller batches.
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+The impact with quota groups enabled can be extreme. The balance operation
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+performs quota group accounting for every extent being relocated, which can
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+have the impact of stalling the file system for an extended period of time.
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+
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__Expected result:__ If possible all the underused chunks are removed, the
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value of `total` in output of `btrfs fi df /path` should be lower than before.
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Check the logs.
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--
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2.16.4
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