There's a long post here on this that might help: https://lucidworks.com/2013/08/23/understanding-transaction-logs-softcommit-and-commit-in-sorlcloud/
Short form: soft commit doesn't flush tlogs, does not start a new tlog, does not close segments, does not open new segments. Hard commit does all of these things. Best, Erick On Sun, May 28, 2017 at 3:59 PM, Nawab Zada Asad Iqbal <khi...@gmail.com> wrote: > Hi, > > SolrCloud document <https://wiki.apache.org/solr/NewSolrCloudDesign> > mentions: > > "The sync can be tunable e.g. flush vs fsync by default can protect against > JVM crashes but not against power failure and can be much faster " > > Does it mean that flush protects against JVM crash but not power failure? > While fsync will protect against both scenarios. > > > Also, this NRT help > <https://cwiki.apache.org/confluence/display/solr/Near+Real+Time+Searching> > explains soft commit as: > "A *soft commit* is much faster since it only makes index changes visible > and does not fsync index files or write a new index descriptor. If the JVM > crashes or there is a loss of power, changes that occurred after the last > *hard > commit* will be lost." > > This is little confusing, as a soft-commit will only happen after a tlog > entry is flushed. Isn't it? Or doesn't tlog work differently for solrcloud > and non-solrCloud configurations. > > > Thanks > Nawab
