3.3.2 Using the Volume Profile Command

The gluster volume profile command displays brick I/O information for each File Operation (FOP) for a volume. The information provided by this command helps you identify where bottlenecks may be in a volume.

Note

Turning on volume profiling may affect system performance, so should be used for troubleshooting and performance monitoring only.

To use the command, use the syntax:

gluster volume profile volume_name options

Use the gluster volume profile -help command to show the full syntax.

This section contains some basic examples on how to use the gluster volume profile command. See the upstream documentation for more information.

Some commands that might be useful are:

gluster volume profile volume_name start

Starts the profiling service for a volume.

gluster volume profile volume_name info

Displays the profiling I/O information of each brick in a volume.

gluster volume profile volume_name stop

Stops the profiling service for a volume.

A more detailed example of using volume profiling follows.

Example 3.18 Using profiling to monitor a volume

This example turns on profiling for a volume, shows the volume profiling information, then turns profiling off. When profiling is started for a volume, two new diagnostic properties are enabled and displayed when you show the volume information (diagnostics.count-fop-hits and diagnostics.latency-measurement).

# gluster volume profile myvolume start
Starting volume profile on myvolume has been successful 
# gluster volume info myvolume
 
Volume Name: myvolume
Type: Distributed-Replicate
Volume ID: ...
Status: Started
Snapshot Count: 0
Number of Bricks: 2 x 3 = 6
Transport-type: tcp
Bricks:
Brick1: node1:/data/glusterfs/myvolume/mybrick/brick
Brick2: node2:/data/glusterfs/myvolume/mybrick/brick
Brick3: node3:/data/glusterfs/myvolume/mybrick/brick
Brick4: node4:/data/glusterfs/myvolume/mybrick/brick
Brick5: node5:/data/glusterfs/myvolume/mybrick/brick
Brick6: node6:/data/glusterfs/myvolume/mybrick/brick
Options Reconfigured:
diagnostics.count-fop-hits: on
diagnostics.latency-measurement: on
transport.address-family: inet
nfs.disable: on
performance.client-io-threads: off
# gluster volume profile myvolume info
Brick: node1:/data/glusterfs/myvolume/mybrick/brick
---------------------------------------------------
Cumulative Stats:
 %-latency   Avg-latency   Min-Latency   Max-Latency   No. of calls         Fop
 ---------   -----------   -----------   -----------   ------------        ----
      0.00       0.00 us       0.00 us       0.00 us            871  RELEASEDIR
      0.17       2.00 us       2.00 us       2.00 us              3     OPENDIR
      3.07      36.67 us      31.00 us      48.00 us              3      LOOKUP
     10.68      95.75 us      15.00 us     141.00 us              4    GETXATTR
     86.08     514.33 us     246.00 us     908.00 us              6     READDIR
 
    Duration: 173875 seconds
   Data Read: 0 bytes
Data Written: 0 bytes
 
Interval 5 Stats:
 
    Duration: 45 seconds
   Data Read: 0 bytes
Data Written: 0 bytes
...
# gluster volume profile myvolume stop
Stopping volume profile on myvolume has been successful