nvlogdump under NV11 produces 5Kb log files without content (4039736)

While using the nvlogdump CLI utility to dump NetVault logs under NV 11.0, the command completes successfully but the log dumped is only 5KB even when the starttime-endtime range covers several weeks.

When opening the log with Support log viewers, it contains only 1 line.

The same process worked fine under 9.2.

Trace on the nvlogdump process shows we are running out of memory:

0 DBCONNCT:06072 23 0 065249.679222 DbExecuteCommand: FAILED [7][out of memory for query result]

This issue resides within the underlying PostgreSQL function PQexec we use with nvlogdump.

The nvlogdump tool calls this PostgreSQL native function which does not allocate sufficiently large buffers to 'store' the query results. 

Workaround:

This issue should not affect small logs covering 24 to 72 hours.

When dumping larger logs which cover longer periods of time, use the -starttime / -endtime switches to reduce the time range so smaller batches of logs are produced, as opposed to storing all results in 1 log.

On busy NVBU servers this "reasonable" time range could vary greatly but as a general guideline, dumping logs that cover less than 5 to 7 days should workaround the out of memory issue.

If older logs are required, use the -starttime / -endtime switches to dump smaller batches of 5 days to 1 week logs.

Status:

Bug 31656 is being investigated and will be resolved in a future version after NV 11.1.