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| author | Christian Schwede <cschwede@redhat.com> | 2016-05-25 09:53:31 +0200 |
|---|---|---|
| committer | Christian Schwede <cschwede@redhat.com> | 2016-05-25 09:53:33 +0200 |
| commit | f1fd50723bb84c4941e949895576733f6eb67793 (patch) | |
| tree | 18c7988166767a43f268fc1faab874be8f9019fd | |
| parent | b3ab715c055283ccfea9a504d6da20741d82e7ad (diff) | |
| download | swift-f1fd50723bb84c4941e949895576733f6eb67793.tar.gz | |
Add dispersion --verbose example to admin guide
Change-Id: I5f9cacedde2a329332ccf744800b6f2453e8b28e
| -rw-r--r-- | doc/source/admin_guide.rst | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/doc/source/admin_guide.rst b/doc/source/admin_guide.rst index d039caac2..2ce58abc8 100644 --- a/doc/source/admin_guide.rst +++ b/doc/source/admin_guide.rst @@ -115,6 +115,40 @@ This will not only display the percentage but will also display a dispersion table that lists partition dispersion by tier. You can use this table to figure out were you need to add capacity or to help tune an :ref:`ring_overload` value. +Now let's take an example with 1 region, 3 zones and 4 devices. Each device has +the same weight, and the ``dispersion --verbose`` might show the following:: + + Dispersion is 50.000000, Balance is 0.000000, Overload is 0.00% + Required overload is 33.333333% + Worst tier is 50.000000 (r1z3) + -------------------------------------------------------------------------- + Tier Parts % Max 0 1 2 3 + -------------------------------------------------------------------------- + r1 256 0.00 3 0 0 0 256 + r1z1 192 0.00 1 64 192 0 0 + r1z1-127.0.0.1 192 0.00 1 64 192 0 0 + r1z1-127.0.0.1/sda 192 0.00 1 64 192 0 0 + r1z2 192 0.00 1 64 192 0 0 + r1z2-127.0.0.2 192 0.00 1 64 192 0 0 + r1z2-127.0.0.2/sda 192 0.00 1 64 192 0 0 + r1z3 256 50.00 1 0 128 128 0 + r1z3-127.0.0.3 256 50.00 1 0 128 128 0 + r1z3-127.0.0.3/sda 192 0.00 1 64 192 0 0 + r1z3-127.0.0.3/sdb 192 0.00 1 64 192 0 0 + + +The first line reports that there are 256 partitions with 3 copies in region 1; +and this is an expected output in this case (single region with 3 replicas) as +reported by the "Max" value. + +However, there is some inbalance in the cluster, more precisely in zone 3. The +"Max" reports a maximum of 1 copy in this zone; however 50.00% of the partitions +are storing 2 replicas in this zone (which is somewhat expected, because there +are more disks in this zone). + +You can now either add more capacity to the other zones, decrease the total +weight in zone 3 or set the overload value to 33.333333%. + ----------------------- Scripting Ring Creation ----------------------- |