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Monitoring your GlusterFS Workload

You can monitor the GlusterFS volumes on different parameters. Monitoring volumes helps in capacity planning and performance tuning tasks of the GlusterFS volume. Using these information, you can identify and troubleshoot issues.

You can use Volume Top and Profile commands to view the performance and identify bottlenecks/hotspots of each brick of a volume. This helps system administrators to get vital performance information whenever performance needs to be probed.

You can also perform statedump of the brick processes and nfs server process of a volume, and also view volume status and volume information.

Running GlusterFS Volume Profile Command

GlusterFS Volume Profile command provides an interface to get the per-brick I/O information for each File Operation (FOP) of a volume. The per brick information helps in identifying bottlenecks in the storage system.

This section describes how to run GlusterFS Volume Profile command by performing the following operations:

Start Profiling

You must start the Profiling to view the File Operation information for each brick.

To start profiling, use following command:

# gluster volume profile start

For example, to start profiling on test-volume:

# gluster volume profile test-volume start
Profiling started on test-volume

When profiling on the volume is started, the following additional options are displayed in the Volume Info:

diagnostics.count-fop-hits: on
diagnostics.latency-measurement: on

Displaying the I/0 Information

You can view the I/O information of each brick by using the following command:

# gluster volume profile info

For example, to see the I/O information on test-volume:

# gluster volume profile test-volume info
Brick: Test:/export/2
Cumulative Stats:

Block                     1b+           32b+           64b+
Size:
       Read:                0              0              0
       Write:             908             28              8

Block                   128b+           256b+         512b+
Size:
       Read:                0               6             4
       Write:               5              23            16

Block                  1024b+          2048b+        4096b+
Size:
       Read:                 0              52           17
       Write:               15             120          846

Block                   8192b+         16384b+      32768b+
Size:
       Read:                52               8           34
       Write:              234             134          286

Block                                  65536b+     131072b+
Size:
       Read:                               118          622
       Write:                             1341          594


%-latency  Avg-      Min-       Max-       calls     Fop
          latency   Latency    Latency
___________________________________________________________
4.82      1132.28   21.00      800970.00   4575    WRITE
5.70       156.47    9.00      665085.00   39163   READDIRP
11.35      315.02    9.00     1433947.00   38698   LOOKUP
11.88     1729.34   21.00     2569638.00    7382   FXATTROP
47.35   104235.02 2485.00     7789367.00     488   FSYNC

------------------

------------------

Duration     : 335

BytesRead    : 94505058

BytesWritten : 195571980

Stop Profiling

You can stop profiling the volume, if you do not need profiling information anymore.

Stop profiling using the following command:

`# gluster volume profile  stop`

For example, to stop profiling on test-volume:

`# gluster volume profile  stop`

`Profiling stopped on test-volume`

Running GlusterFS Volume TOP Command

GlusterFS Volume Top command allows you to view the glusterfs bricks’ performance metrics like read, write, file open calls, file read calls, file write calls, directory open calls, and directory real calls. The top command displays up to 100 results.

This section describes how to run and view the results for the following GlusterFS Top commands:

Viewing Open fd Count and Maximum fd Count

You can view both current open fd count (list of files that are currently the most opened and the count) on the brick and the maximum open fd count (count of files that are the currently open and the count of maximum number of files opened at any given point of time, since the servers are up and running). If the brick name is not specified, then open fd metrics of all the bricks belonging to the volume will be displayed.

  • View open fd count and maximum fd count using the following command:

    # gluster volume top open [brick ] [list-cnt ]

    For example, to view open fd count and maximum fd count on brick server:/export of test-volume and list top 10 open calls:

    # gluster volume top open brick list-cnt

    Brick: server:/export/dir1

    Current open fd's: 34 Max open fd's: 209

                 ==========Open file stats========
    
    open            file name
    call count
    
    2               /clients/client0/~dmtmp/PARADOX/
                    COURSES.DB
    
    11              /clients/client0/~dmtmp/PARADOX/
                    ENROLL.DB
    
    11              /clients/client0/~dmtmp/PARADOX/
                    STUDENTS.DB
    
    10              /clients/client0/~dmtmp/PWRPNT/
                    TIPS.PPT
    
    10              /clients/client0/~dmtmp/PWRPNT/
                    PCBENCHM.PPT
    
    9               /clients/client7/~dmtmp/PARADOX/
                    STUDENTS.DB
    
    9               /clients/client1/~dmtmp/PARADOX/
                    STUDENTS.DB
    
    9               /clients/client2/~dmtmp/PARADOX/
                    STUDENTS.DB
    
    9               /clients/client0/~dmtmp/PARADOX/
                    STUDENTS.DB
    
    9               /clients/client8/~dmtmp/PARADOX/
                    STUDENTS.DB
    

Viewing Highest File Read Calls

You can view highest read calls on each brick. If brick name is not specified, then by default, list of 100 files will be displayed.

  • View highest file Read calls using the following command:

    # gluster volume top read [brick ] [list-cnt ]

    For example, to view highest Read calls on brick server:/export of test-volume:

    # gluster volume top read brick list-cnt

    Brick: server:/export/dir1

              ==========Read file stats========
    
    read              filename
    call count
    
    116              /clients/client0/~dmtmp/SEED/LARGE.FIL
    
    64               /clients/client0/~dmtmp/SEED/MEDIUM.FIL
    
    54               /clients/client2/~dmtmp/SEED/LARGE.FIL
    
    54               /clients/client6/~dmtmp/SEED/LARGE.FIL
    
    54               /clients/client5/~dmtmp/SEED/LARGE.FIL
    
    54               /clients/client0/~dmtmp/SEED/LARGE.FIL
    
    54               /clients/client3/~dmtmp/SEED/LARGE.FIL
    
    54               /clients/client4/~dmtmp/SEED/LARGE.FIL
    
    54               /clients/client9/~dmtmp/SEED/LARGE.FIL
    
    54               /clients/client8/~dmtmp/SEED/LARGE.FIL
    

Viewing Highest File Write Calls

You can view list of files which has highest file write calls on each brick. If brick name is not specified, then by default, list of 100 files will be displayed.

  • View highest file Write calls using the following command:

    # gluster volume top write [brick ] [list-cnt ]

    For example, to view highest Write calls on brick server:/export of test-volume:

    # gluster volume top write brick list-cnt

    Brick: server:/export/dir1

                   ==========Write file stats========
    write call count   filename
    
    83                /clients/client0/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client7/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client1/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client2/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client0/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client8/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client5/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client4/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client6/~dmtmp/SEED/LARGE.FIL
    
    59                /clients/client3/~dmtmp/SEED/LARGE.FIL
    

Viewing Highest Open Calls on Directories

You can view list of files which has highest open calls on directories of each brick. If brick name is not specified, then the metrics of all the bricks belonging to that volume will be displayed.

  • View list of open calls on each directory using the following command:

    # gluster volume top opendir [brick ] [list-cnt ]

    For example, to view open calls on brick server:/export/ of test-volume:

    # gluster volume top opendir brick list-cnt

    Brick: server:/export/dir1

             ==========Directory open stats========
    
    Opendir count     directory name
    
    1001              /clients/client0/~dmtmp
    
    454               /clients/client8/~dmtmp
    
    454               /clients/client2/~dmtmp
    
    454               /clients/client6/~dmtmp
    
    454               /clients/client5/~dmtmp
    
    454               /clients/client9/~dmtmp
    
    443               /clients/client0/~dmtmp/PARADOX
    
    408               /clients/client1/~dmtmp
    
    408               /clients/client7/~dmtmp
    
    402               /clients/client4/~dmtmp
    

Viewing Highest Read Calls on Directory

You can view list of files which has highest directory read calls on each brick. If brick name is not specified, then the metrics of all the bricks belonging to that volume will be displayed.

  • View list of highest directory read calls on each brick using the following command:

    # gluster volume top test-volume readdir [brick BRICK] [list-cnt {0..100}]

    For example, to view highest directory read calls on brick server:/export of test-volume:

    # gluster volume top test-volume readdir brick server:/export list-cnt 10

    Brick:

    ==========Directory readdirp stats========
    
    readdirp count           directory name
    
    1996                    /clients/client0/~dmtmp
    
    1083                    /clients/client0/~dmtmp/PARADOX
    
    904                     /clients/client8/~dmtmp
    
    904                     /clients/client2/~dmtmp
    
    904                     /clients/client6/~dmtmp
    
    904                     /clients/client5/~dmtmp
    
    904                     /clients/client9/~dmtmp
    
    812                     /clients/client1/~dmtmp
    
    812                     /clients/client7/~dmtmp
    
    800                     /clients/client4/~dmtmp
    

Viewing List of Read Performance on each Brick

You can view the read throughput of files on each brick. If brick name is not specified, then the metrics of all the bricks belonging to that volume will be displayed. The output will be the read throughput.

       ==========Read throughput file stats========

read         filename                         Time
through
put(MBp
s)

2570.00    /clients/client0/~dmtmp/PWRPNT/      -2011-01-31
           TRIDOTS.POT                      15:38:36.894610
2570.00    /clients/client0/~dmtmp/PWRPNT/      -2011-01-31
           PCBENCHM.PPT                     15:38:39.815310
2383.00    /clients/client2/~dmtmp/SEED/        -2011-01-31
           MEDIUM.FIL                       15:52:53.631499

2340.00    /clients/client0/~dmtmp/SEED/        -2011-01-31
           MEDIUM.FIL                       15:38:36.926198

2299.00   /clients/client0/~dmtmp/SEED/         -2011-01-31
          LARGE.FIL                         15:38:36.930445

2259.00   /clients/client0/~dmtmp/PARADOX/      -2011-01-31
          COURSES.X04                       15:38:40.549919

2221.00   /clients/client0/~dmtmp/PARADOX/      -2011-01-31
          STUDENTS.VAL                      15:52:53.298766

2221.00   /clients/client3/~dmtmp/SEED/         -2011-01-31
          COURSES.DB                        15:39:11.776780

2184.00   /clients/client3/~dmtmp/SEED/         -2011-01-31
          MEDIUM.FIL                        15:39:10.251764

2184.00   /clients/client5/~dmtmp/WORD/         -2011-01-31
          BASEMACH.DOC                      15:39:09.336572

This command will initiate a dd for the specified count and block size and measures the corresponding throughput.

  • View list of read performance on each brick using the following command:

    # gluster volume top read-perf [bs count ] [brick ] [list-cnt ]

    For example, to view read performance on brick server:/export/ of test-volume, 256 block size of count 1, and list count 10:

    # gluster volume top read-perf bs 256 count 1 brick list-cnt

    Brick: server:/export/dir1 256 bytes (256 B) copied, Throughput: 4.1 MB/s

           ==========Read throughput file stats========
    
    read         filename                         Time
    through
    put(MBp
    s)
    
    2912.00   /clients/client0/~dmtmp/PWRPNT/    -2011-01-31
               TRIDOTS.POT                   15:38:36.896486
    
    2570.00   /clients/client0/~dmtmp/PWRPNT/    -2011-01-31
               PCBENCHM.PPT                  15:38:39.815310
    
    2383.00   /clients/client2/~dmtmp/SEED/      -2011-01-31
               MEDIUM.FIL                    15:52:53.631499
    
    2340.00   /clients/client0/~dmtmp/SEED/      -2011-01-31
               MEDIUM.FIL                    15:38:36.926198
    
    2299.00   /clients/client0/~dmtmp/SEED/      -2011-01-31
               LARGE.FIL                     15:38:36.930445
    
    2259.00  /clients/client0/~dmtmp/PARADOX/    -2011-01-31
              COURSES.X04                    15:38:40.549919
    
    2221.00  /clients/client9/~dmtmp/PARADOX/    -2011-01-31
              STUDENTS.VAL                   15:52:53.298766
    
    2221.00  /clients/client8/~dmtmp/PARADOX/    -2011-01-31
             COURSES.DB                      15:39:11.776780
    
    2184.00  /clients/client3/~dmtmp/SEED/       -2011-01-31
              MEDIUM.FIL                     15:39:10.251764
    
    2184.00  /clients/client5/~dmtmp/WORD/       -2011-01-31
             BASEMACH.DOC                    15:39:09.336572
    

Viewing List of Write Performance on each Brick

You can view list of write throughput of files on each brick. If brick name is not specified, then the metrics of all the bricks belonging to that volume will be displayed. The output will be the write throughput.

This command will initiate a dd for the specified count and block size and measures the corresponding throughput. To view list of write performance on each brick:

  • View list of write performance on each brick using the following command:

    # gluster volume top write-perf [bs count ] [brick ] [list-cnt ]

    For example, to view write performance on brick server:/export/ of test-volume, 256 block size of count 1, and list count 10:

    # gluster volume top write-perf bs 256 count 1 brick list-cnt

    Brick: server:/export/dir1

    256 bytes (256 B) copied, Throughput: 2.8 MB/s

           ==========Write throughput file stats========
    
    write                filename                 Time
    throughput
    (MBps)
    
    1170.00    /clients/client0/~dmtmp/SEED/     -2011-01-31
               SMALL.FIL                     15:39:09.171494
    
    1008.00    /clients/client6/~dmtmp/SEED/     -2011-01-31
               LARGE.FIL                      15:39:09.73189
    
    949.00    /clients/client0/~dmtmp/SEED/      -2011-01-31
              MEDIUM.FIL                     15:38:36.927426
    
    936.00   /clients/client0/~dmtmp/SEED/       -2011-01-31
             LARGE.FIL                        15:38:36.933177
    897.00   /clients/client5/~dmtmp/SEED/       -2011-01-31
             MEDIUM.FIL                       15:39:09.33628
    
    897.00   /clients/client6/~dmtmp/SEED/       -2011-01-31
             MEDIUM.FIL                       15:39:09.27713
    
    885.00   /clients/client0/~dmtmp/SEED/       -2011-01-31
              SMALL.FIL                      15:38:36.924271
    
    528.00   /clients/client5/~dmtmp/SEED/       -2011-01-31
             LARGE.FIL                        15:39:09.81893
    
    516.00   /clients/client6/~dmtmp/ACCESS/    -2011-01-31
             FASTENER.MDB                    15:39:01.797317
    

Displaying Volume Information

You can display information about a specific volume, or all volumes, as needed.

  • Display information about a specific volume using the following command:

    # gluster volume info ``VOLNAME

    For example, to display information about test-volume:

    # gluster volume info test-volume
    Volume Name: test-volume
    Type: Distribute
    Status: Created
    Number of Bricks: 4
    Bricks:
    Brick1: server1:/exp1
    Brick2: server2:/exp2
    Brick3: server3:/exp3
    Brick4: server4:/exp4
    
  • Display information about all volumes using the following command:

    # gluster volume info all

    # gluster volume info all
    
    Volume Name: test-volume
    Type: Distribute
    Status: Created
    Number of Bricks: 4
    Bricks:
    Brick1: server1:/exp1
    Brick2: server2:/exp2
    Brick3: server3:/exp3
    Brick4: server4:/exp4
    
    Volume Name: mirror
    Type: Distributed-Replicate
    Status: Started
    Number of Bricks: 2 X 2 = 4
    Bricks:
    Brick1: server1:/brick1
    Brick2: server2:/brick2
    Brick3: server3:/brick3
    Brick4: server4:/brick4
    
    Volume Name: Vol
    Type: Distribute
    Status: Started
    Number of Bricks: 1
    Bricks:
    Brick: server:/brick6
    

Performing Statedump on a Volume

Statedump is a mechanism through which you can get details of all internal variables and state of the glusterfs process at the time of issuing the command.You can perform statedumps of the brick processes and nfs server process of a volume using the statedump command. The following options can be used to determine what information is to be dumped:

  • mem - Dumps the memory usage and memory pool details of the bricks.

  • iobuf - Dumps iobuf details of the bricks.

  • priv - Dumps private information of loaded translators.

  • callpool - Dumps the pending calls of the volume.

  • fd - Dumps the open fd tables of the volume.

  • inode - Dumps the inode tables of the volume.

To display volume statedump

  • Display statedump of a volume or NFS server using the following command:

    # gluster volume statedump [nfs] [all|mem|iobuf|callpool|priv|fd|inode]

    For example, to display statedump of test-volume:

    # gluster volume statedump test-volume
    Volume statedump successful
    

    The statedump files are created on the brick servers in the/tmp directory or in the directory set using server.statedump-path volume option. The naming convention of the dump file is <brick-path>.<brick-pid>.dump.

  • By defult, the output of the statedump is stored at /tmp/<brickname.PID.dump> file on that particular server. Change the directory of the statedump file using the following command:

    # gluster volume set server.statedump-path

    For example, to change the location of the statedump file of test-volume:

    # gluster volume set test-volume server.statedump-path /usr/local/var/log/glusterfs/dumps/
    Set volume successful
    

    You can view the changed path of the statedump file using the following command:

    # gluster volume info

Displaying Volume Status

You can display the status information about a specific volume, brick or all volumes, as needed. Status information can be used to understand the current status of the brick, nfs processes, and overall file system. Status information can also be used to monitor and debug the volume information. You can view status of the volume along with the following details:

  • detail - Displays additional information about the bricks.

  • clients - Displays the list of clients connected to the volume.

  • mem - Displays the memory usage and memory pool details of the bricks.

  • inode - Displays the inode tables of the volume.

  • fd - Displays the open fd (file descriptors) tables of the volume.

  • callpool - Displays the pending calls of the volume.

To display volume status

  • Display information about a specific volume using the following command:

    # gluster volume status [all| []] [detail|clients|mem|inode|fd|callpool]

    For example, to display information about test-volume:

    # gluster volume status test-volume
    STATUS OF VOLUME: test-volume
    BRICK                           PORT   ONLINE   PID
    --------------------------------------------------------
    arch:/export/1                  24009   Y       22445
    --------------------------------------------------------
    arch:/export/2                  24010   Y       22450
    
  • Display information about all volumes using the following command:

    # gluster volume status all

    # gluster volume status all
    STATUS OF VOLUME: volume-test
    BRICK                           PORT   ONLINE   PID
    --------------------------------------------------------
    arch:/export/4                  24010   Y       22455
    
    STATUS OF VOLUME: test-volume
    BRICK                           PORT   ONLINE   PID
    --------------------------------------------------------
    arch:/export/1                  24009   Y       22445
    --------------------------------------------------------
    arch:/export/2                  24010   Y       22450
    
  • Display additional information about the bricks using the following command:

    # gluster volume status detail

    For example, to display additional information about the bricks of test-volume:

    # gluster volume status test-volume details
    STATUS OF VOLUME: test-volume
    -------------------------------------------
    Brick                : arch:/export/1
    Port                 : 24009
    Online               : Y
    Pid                  : 16977
    File System          : rootfs
    Device               : rootfs
    Mount Options        : rw
    Disk Space Free      : 13.8GB
    Total Disk Space     : 46.5GB
    Inode Size           : N/A
    Inode Count          : N/A
    Free Inodes          : N/A
    
    Number of Bricks: 1
    Bricks:
    Brick: server:/brick6
    
  • Display the list of clients accessing the volumes using the following command:

    # gluster volume status test-volume clients

    For example, to display the list of clients connected to test-volume:

    # gluster volume status test-volume clients
    Brick : arch:/export/1
    Clients connected : 2
    Hostname          Bytes Read   BytesWritten
    --------          ---------    ------------
    127.0.0.1:1013    776          676
    127.0.0.1:1012    50440        51200
    
  • Display the memory usage and memory pool details of the bricks using the following command:

    # gluster volume status test-volume mem

    For example, to display the memory usage and memory pool details of the bricks of test-volume:

    Memory status for volume : test-volume
    ----------------------------------------------
    Brick : arch:/export/1
    Mallinfo
    --------
    Arena    : 434176
    Ordblks  : 2
    Smblks   : 0
    Hblks    : 12
    Hblkhd   : 40861696
    Usmblks  : 0
    Fsmblks  : 0
    Uordblks : 332416
    Fordblks : 101760
    Keepcost : 100400
    
    Mempool Stats
    -------------
    Name                               HotCount ColdCount PaddedSizeof AllocCount MaxAlloc
    ----                               -------- --------- ------------ ---------- --------
    test-volume-server:fd_t                0     16384           92         57        5
    test-volume-server:dentry_t           59       965           84         59       59
    test-volume-server:inode_t            60       964          148         60       60
    test-volume-server:rpcsvc_request_t    0       525         6372        351        2
    glusterfs:struct saved_frame           0      4096          124          2        2
    glusterfs:struct rpc_req               0      4096         2236          2        2
    glusterfs:rpcsvc_request_t             1       524         6372          2        1
    glusterfs:call_stub_t                  0      1024         1220        288        1
    glusterfs:call_stack_t                 0      8192         2084        290        2
    glusterfs:call_frame_t                 0     16384          172       1728        6
    
  • Display the inode tables of the volume using the following command:

    # gluster volume status inode

    For example, to display the inode tables of the test-volume:

    # gluster volume status test-volume inode
    inode tables for volume test-volume
    ----------------------------------------------
    Brick : arch:/export/1
    Active inodes:
    GFID                                            Lookups            Ref   IA type
    ----                                            -------            ---   -------
    6f3fe173-e07a-4209-abb6-484091d75499                  1              9         2
    370d35d7-657e-44dc-bac4-d6dd800ec3d3                  1              1         2
    
    LRU inodes:
    GFID                                            Lookups            Ref   IA type
    ----                                            -------            ---   -------
    80f98abe-cdcf-4c1d-b917-ae564cf55763                  1              0         1
    3a58973d-d549-4ea6-9977-9aa218f233de                  1              0         1
    2ce0197d-87a9-451b-9094-9baa38121155                  1              0         2
    
  • Display the open fd tables of the volume using the following command:

    # gluster volume status fd

    For example, to display the open fd tables of the test-volume:

    # gluster volume status test-volume fd
    
    FD tables for volume test-volume
    ----------------------------------------------
    Brick : arch:/export/1
    Connection 1:
    RefCount = 0  MaxFDs = 128  FirstFree = 4
    FD Entry            PID                 RefCount            Flags
    --------            ---                 --------            -----
    0                   26311               1                   2
    1                   26310               3                   2
    2                   26310               1                   2
    3                   26311               3                   2
    
    Connection 2:
    RefCount = 0  MaxFDs = 128  FirstFree = 0
    No open fds
    
    Connection 3:
    RefCount = 0  MaxFDs = 128  FirstFree = 0
    No open fds
    
  • Display the pending calls of the volume using the following command:

    # gluster volume status callpool

    Each call has a call stack containing call frames.

    For example, to display the pending calls of test-volume:

    # gluster volume status test-volume
    
    Pending calls for volume test-volume
    ----------------------------------------------
    Brick : arch:/export/1
    Pending calls: 2
    Call Stack1
     UID    : 0
     GID    : 0
     PID    : 26338
     Unique : 192138
     Frames : 7
     Frame 1
      Ref Count   = 1
      Translator  = test-volume-server
      Completed   = No
     Frame 2
      Ref Count   = 0
      Translator  = test-volume-posix
      Completed   = No
      Parent      = test-volume-access-control
      Wind From   = default_fsync
      Wind To     = FIRST_CHILD(this)->fops->fsync
     Frame 3
      Ref Count   = 1
      Translator  = test-volume-access-control
      Completed   = No
      Parent      = repl-locks
      Wind From   = default_fsync
      Wind To     = FIRST_CHILD(this)->fops->fsync
     Frame 4
      Ref Count   = 1
      Translator  = test-volume-locks
      Completed   = No
      Parent      = test-volume-io-threads
      Wind From   = iot_fsync_wrapper
      Wind To     = FIRST_CHILD (this)->fops->fsync
     Frame 5
      Ref Count   = 1
      Translator  = test-volume-io-threads
      Completed   = No
      Parent      = test-volume-marker
      Wind From   = default_fsync
      Wind To     = FIRST_CHILD(this)->fops->fsync
     Frame 6
      Ref Count   = 1
      Translator  = test-volume-marker
      Completed   = No
      Parent      = /export/1
      Wind From   = io_stats_fsync
      Wind To     = FIRST_CHILD(this)->fops->fsync
     Frame 7
      Ref Count   = 1
      Translator  = /export/1
      Completed   = No
      Parent      = test-volume-server
      Wind From   = server_fsync_resume
      Wind To     = bound_xl->fops->fsync