store_sos

Man page for the LDMS store_sos plugin

Date:: 21 Dec 2015
Manual section:: 7
Manual group:: LDMS store

SYNOPSIS

load name=NAME plugin=store_sos

DESCRIPTION

The store_sos plugin implements an interface between the ldmsd storage infrastructure and the Scalable Object Store (SOS).

To build the store_sos plugin, specify the –with-sos=PATH flag where PATH is the location of the SOS installaction.

This plugin is multi-instance capable.

STORE_SOS INIT CONFIGURATION ATTRIBUTE SYNTAX

config

name=NAME path=PATH [mode=OCTAL] [backend=BACKEND]

name=NAME: This is the storage plugin instance name
path=PATH: The store will place containers into the directory named PATH.

This directory must exist. The CONTAINER name is specifed when

configing the storage policy.
mode=MODE (default is 0660): An octal number representing the permission bits used when new files

are created for the CONTAINER. See the open(3) system call.
backend=BACKEND (default is “mmos”): The BACKEND specifies the storage strategy that will be used for

objects stored in the CONTAINER. The BACKEND is one of “mmos” or “lsos”

The “mmos” backend is a Memory Mapped Object Store (MMOS). This storage

strategy uses the mmap() system call to map file system memory into the

address space of the ldmsd. This strategy is very efficient for solid

state storage devices and local filesystems, but can be very

inefficient for distributed file systems. The “lsos” backend is a Log

Structured Object Store (LSOS) that uses standard read()/write() and

compression to store data in the file system. This strategy is less

efficient for object creation and indexing, but is more efficent for

distributed storage; using typically less than 1/8 of the storage

consumed by MMOS.

NOTES

The configuration files do not specify partition names. This is done automatically and is an epoch timestamp. See the time command.
Management of partitions is done outside of ldmsd. See the sos-part command.

BUGS

No known bugs.

EXAMPLES

Simple store_sos Configuration

This will store metric set data with the schema meminfo into the container /var/tmp/ldms. The example below are the relevant lines in the ldmsd configuration file.

load name=ss1 plugin=store_sos
config name=ss1 path=/var/tmp
strgp_add name=strgp_sos plugin=ss1 container=ldms schema=meminfo
strgp_start name=strgp_sos plugin=ss1 container=ldms schema=meminfo

Store with Two Backends

This will store metric set data as described in decomp.conf to two different containers: one using the MMOS backend and another using the LSOS backend.

You can compare the performance of these two backends using the store_time_stats command.

The relevant lines from a configuration file are as follows:

load name=mmos plugin=store_sos
config name=mmos path=/var/tmp/mmos backend=mmos mode=0777

load name=lsos plugin=store_sos
config name=lsos path=/var/tmp/lsos backend=lsos mode=0777

strgp_add name=lsos plugin=lsos container=ldms \
   decomposition=/opt/ovis/etc/decomp.json regex=.*
strgp_prdcr_add name=lsos regex=.* \
   strgp_start name=lsos

strgp_add name=mmos plugin=mmos container=ldms \
    decomposition=/opt/ovis/etc/decomp.json regex=.*
strgp_prdcr_add name=mmos regex=.*

strgp_start name=mmos
strgp_start name=lmos

Examine Storage Plugin Performance

The ldmsd_controller store_time_stats command can be used to evaluate plugin performance:

ldmsd_controller -a munge -p 10002
Welcome to the LDMSD control processor
sock:localhost:10002> store_time_stats
=========================================================================================================================================
<   Minimum Value          -   Minimum Average value
>   Maximum Value          +   Maximum Average value
=========================================================================================================================================
Schema           Min (us)        Avg (us)        Max (us)        Min Timestamp        Max Timestamp     # of Sets    Count
------------------------- --------------- --------------- --------------- -------------------- -------------------- ---------- ----------
    file_importer.fi.helm          1.2800          3.3632          9.9840           1775162441           1775163540          1        699
<-   file_importer.fi.smart2          1.0240          2.1149          7.1680           1775162271           1775164051          1        696
>+           perfevent2          5.3760        228.9463      37693.9520           1775162903           1775162207          1      13992
=========================================================================================================================================
Storage Policy       Min (us)        Avg (us)        Max (us)        Min Timestamp        Max Timestamp     # of Sets    Count
------------------------- --------------- --------------- --------------- -------------------- -------------------- ---------- ----------
<>+  csv                         1.0240        239.4822      37693.9520           1775162271           1775162207          3       5129
------------------ --------------- --------------- --------------- -------------------- -------------------- ---------- ----------
     lsos                        1.0240        230.7347      34880.5120           1775162331           1775162204          3       5129
------------------ --------------- --------------- --------------- -------------------- -------------------- ---------- ----------
  -  mmos                        1.0240        155.0978      26222.0800           1775164071           1775163461          3       5129
 ------------------ --------------- --------------- --------------- -------------------- -------------------- ---------- ----------

Number of store operations per second: 6.4863
Percentages of each stage:
commit         :   84.53%
queue          :   10.40%
decomp         :    4.34%
prep           :    0.52%
wait           :    0.22%