Commit 5f715404 authored by Iustin Pop's avatar Iustin Pop
Browse files

Document the gain options in hbal's manpage

parent 848b65c9
......@@ -25,6 +25,7 @@ Algorithm options:
.BI "[ --min-disk " disk-ratio " ]"
.BI "[ -l " limit " ]"
.BI "[ -e " score " ]"
.BI "[ -g " delta " ] [ --min-gain-limit " threshold " ]"
.BI "[ -O " name... " ]"
.B "[ --no-disk-moves ]"
.BI "[ -U " util-file " ]"
......@@ -396,6 +397,22 @@ The default value of the parameter is currently \fI1e-9\fR (chosen
empirically).
.RE
.TP
.BI "-g" delta ", --min-gain=" delta
Since the balancing algorithm can sometimes result in just very tiny
improvements, that bring less gain that they cost in relocation time,
this parameter (defaulting to 0.01) represents the minimum gain we
require during a step, to continue balancing.
.TP
.BI "--min-gain-limit=" threshold
The above min-gain option will only take effect if the cluster score
is already below \fIthreshold\fR (defaults to 0.1). The rationale
behind this setting is that at high cluster scores (badly balanced
clusters), we don't want to abort the rebalance too quickly, as later
gains might still be significant. However, under the threshold, the
total gain is only the threshold value, so we can exit early.
.TP
.BI "--no-disk-moves"
This parameter prevents hbal from using disk move (i.e. "gnt\-instance
......
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