Plugin_daos_sampler
- Date:
28 Apr 2022
NAME
Plugin_daos_sampler - man page for the LDMS DAOS sampler plugin
SYNOPSIS
DESCRIPTION
The daos_sampler plugin collects DAOS telemetry from local DAOS I/O Engine instances.
CONFIGURATION ATTRIBUTE SYNTAX
The daos_sampler plugin uses the sampler_base base class. This man page only covers the configuration attributes specific to this plugin; see ldms_sampler_base.man for the attributes of the base class.
- name=<plugin_name>
- This MUST be daos_sampler.
- producer=$HOSTNAME
- The $HOSTNAME variable provides a good unique producer ID.
- engine_count=2
- The default is 2; don’t change it unless the number of per-server engines is different.
- target_count=8
- The default is 8; don’t change it unless the number of targets per engine is different.
SAMPLE FORMAT
The DAOS telemetry is exposed as a set of trees, with the system name as the root:
$system/$rank/$target - Per-engine target metrics not associated with a pool
$system/$rank/$pool - Per-engine top-level pool metrics
$system/$rank/$pool/$target - Per-engine target metrics associated with a pool
Under each tree is a set of metrics in either counter or gauge format. Counters are monotonically-increasing uint64 values; gauges are instantaneous-read uint64 values that can vary up or down. Certain gauge metrics may have associated statistics in min/max/count/mean/stddev format.
EXAMPLE SAMPLER USAGE
Start ldmsd as usual, for example:
$ ldmsd -m1MB -x sock:10444 -F -c /path/to/sampler.conf
NOTE: The default memory size (512KB) may be too small for the number of metrics collected. Larger sizes may be specified for a large number of pools.
Once ldmsd is running, it is possible to check that the DAOS telemetry appears in the output of ldms_ls, for example:
$ ldms_ls -h localhost -x sock -p 10444 -l
daos_server/0/0: consistent, last update: Wed Aug 25 18:40:25 2021 +0000 [653335us]
M char[] system "daos_server"
M u32 rank 0
M u32 target 0
D u64 io/latency/update/256B 0
D u64 io/latency/update/256B/min 0
D u64 io/latency/update/256B/max 0
D u64 io/latency/update/256B/samples 0
D d64 io/latency/update/256B/mean 0.000000
D d64 io/latency/update/256B/stddev 0.000000
D u64 io/latency/update/32KB 611
D u64 io/latency/update/32KB/min 611
D u64 io/latency/update/32KB/max 611
D u64 io/latency/update/32KB/samples 1
D d64 io/latency/update/32KB/mean 611.000000
D d64 io/latency/update/32KB/stddev 0.000000
D u64 io/latency/update/64KB 0
D u64 io/latency/update/64KB/min 0
D u64 io/latency/update/64KB/max 0
D u64 io/latency/update/64KB/samples 0
D d64 io/latency/update/64KB/mean 0.000000
D d64 io/latency/update/64KB/stddev 0.000000
D u64 io/latency/update/128KB 1018
D u64 io/latency/update/128KB/min 567
D u64 io/latency/update/128KB/max 1214
D u64 io/latency/update/128KB/samples 8
D d64 io/latency/update/128KB/mean 828.000000
D d64 io/latency/update/128KB/stddev 238.011404