c853f382db
= Old behavior For vdev sizes 100GB to 50TB we keep ~200 metaslabs per vdev and the metaslab size grows from 512MB to 256GB. For vdev's bigger than that we start increasing the number of metaslabs until we hit the 128K limit. = New Behavior For vdev sizes 100GB to 3TB we keep ~200 metaslabs per vdev and the metaslab size grows from 512MB to 16GB. For vdev's bigger than that we start increasing the number of metaslabs until we hit the 128K limit. = Reasoning The old behavior makes metaslabs grow in size when the vdev range is between 3TB (ms_size 16GB) and 32PB (ms_size 256GB). Even though keeping the number of metaslabs is good in terms of potential number of I/Os per TXG, these bigger metaslabs take longer to be loaded and after they are loaded they can take up a lot of memory because of their range trees. This change tries to put a boundary in memory and loading time for the specific range of vdev sizes. Reviewed-by: Matt Ahrens <mahrens@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Don Brady <don.brady@delphix.com> Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com> Closes #8324 |
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