documentation update regarding placement of WAL files (to reflect 1.5+ functionality)
Signed-off-by: Josh Elser <els...@apache.org> Project: http://git-wip-us.apache.org/repos/asf/accumulo/repo Commit: http://git-wip-us.apache.org/repos/asf/accumulo/commit/1f99e6e1 Tree: http://git-wip-us.apache.org/repos/asf/accumulo/tree/1f99e6e1 Diff: http://git-wip-us.apache.org/repos/asf/accumulo/diff/1f99e6e1 Branch: refs/heads/1.6.0-SNAPSHOT Commit: 1f99e6e14609b3aee51cdeb998b0ee258d959911 Parents: 52ef7c6 Author: Arshak Navruzyan <arsh...@gmail.com> Authored: Sun Jan 19 10:37:38 2014 -0800 Committer: Josh Elser <els...@apache.org> Committed: Mon Jan 20 12:14:40 2014 -0500 ---------------------------------------------------------------------- .../accumulo_user_manual/chapters/administration.tex | 6 +++--- .../main/latex/accumulo_user_manual/chapters/design.tex | 11 +++++------ 2 files changed, 8 insertions(+), 9 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/accumulo/blob/1f99e6e1/docs/src/main/latex/accumulo_user_manual/chapters/administration.tex ---------------------------------------------------------------------- diff --git a/docs/src/main/latex/accumulo_user_manual/chapters/administration.tex b/docs/src/main/latex/accumulo_user_manual/chapters/administration.tex index 204f549..28b1033 100644 --- a/docs/src/main/latex/accumulo_user_manual/chapters/administration.tex +++ b/docs/src/main/latex/accumulo_user_manual/chapters/administration.tex @@ -378,9 +378,9 @@ Accumulo processes each write to a set of log files. By default these are found In the event of TabletServer failure or error on shutting Accumulo down, some mutations may not have been minor compacted to HDFS properly. In this case, Accumulo will automatically reapply such mutations from the write-ahead log -either when the tablets from the failed server are reassigned by the Master, in the -case of a single TabletServer failure or the next time Accumulo starts, in the event of -failure during shutdown. +either when the tablets from the failed server are reassigned by the Master (in the +case of a single TabletServer failure) or the next time Accumulo starts (in the event of +failure during shutdown). Recovery is performed by asking a tablet server to sort the logs so that tablets can easily find their missing updates. The sort status of each file is displayed on http://git-wip-us.apache.org/repos/asf/accumulo/blob/1f99e6e1/docs/src/main/latex/accumulo_user_manual/chapters/design.tex ---------------------------------------------------------------------- diff --git a/docs/src/main/latex/accumulo_user_manual/chapters/design.tex b/docs/src/main/latex/accumulo_user_manual/chapters/design.tex index d3c162b..72e1ddf 100644 --- a/docs/src/main/latex/accumulo_user_manual/chapters/design.tex +++ b/docs/src/main/latex/accumulo_user_manual/chapters/design.tex @@ -148,13 +148,12 @@ introduced in Accumulo 1.4. This is discussed in more detail later. If a TabletServer fails, the Master detects it and automatically reassigns the tablets assigned from the failed server to other servers. Any key-value pairs that were in memory at the time the TabletServer fails are automatically reapplied from the Write-Ahead -Log to prevent any loss of data. +Log(WAL) to prevent any loss of data. -The Master will coordinate the copying of write-ahead logs to HDFS so the logs -are available to all tablet servers. To make recovery efficient, the updates -within a log are grouped by tablet. TabletServers can quickly apply the -mutations from the sorted logs that are destined for the tablets they have now -been assigned. +Tablet servers write their WALs directly to HDFS so the logs are available to all tablet +servers for recovery. To make the recovery process efficient, the updates within a log are +grouped by tablet. TabletServers can quickly apply the mutations from the sorted logs +that are destined for the tablets they have now been assigned. TabletServer failures are noted on the Master's monitor page, accessible via\\ \mbox{http://master-address:50095/monitor}.
