CTDB-STATISTICS(7)

NAME
ctdb-statistics - CTDB statistics output

OVERALL STATISTICS

CTDB maintains information about various messages communicated and some of the important operations per node. See the ctdb(1) commands statistics and statisticsreset for displaying statistics.

  Example: ctdb statistics

    CTDB version 1
    Current time of statistics  :                Fri Sep 12 13:32:32 2014
    Statistics collected since  : (000 01:49:20) Fri Sep 12 11:43:12 2014
     num_clients                        6
     frozen                             0
     recovering                         0
     num_recoveries                     2
     client_packets_sent           281293
     client_packets_recv           296317
     node_packets_sent             452387
     node_packets_recv             182394
     keepalive_packets_sent          3927
     keepalive_packets_recv          3928
     node
         req_call                   48605
         reply_call                     1
         req_dmaster                23404
         reply_dmaster              24917
         reply_error                    0
         req_message                  958
         req_control               197513
         reply_control             153705
     client
         req_call                  130866
         req_message                  770
         req_control               168921
     timeouts
         call                           0
         control                        0
         traverse                       0
     locks
         num_calls                    220
         num_current                    0
         num_pending                    0
         num_failed                     0
     total_calls                   130866
     pending_calls                      0
     childwrite_calls                   1
     pending_childwrite_calls             0
     memory_used                   334490
     max_hop_count                     18
     total_ro_delegations               2
     total_ro_revokes                   2
     hop_count_buckets: 42816 5464 26 1 0 0 0 0 0 0 0 0 0 0 0 0
     lock_buckets: 9 165 14 15 7 2 2 0 0 0 0 0 0 0 0 0
     locks_latency      MIN/AVG/MAX     0.000685/0.160302/6.369342 sec out of 214
     reclock_ctdbd      MIN/AVG/MAX     0.004940/0.004969/0.004998 sec out of 2
     reclock_recd       MIN/AVG/MAX     0.000000/0.000000/0.000000 sec out of 0
     call_latency       MIN/AVG/MAX     0.000006/0.000719/4.562991 sec out of 126626
     childwrite_latency MIN/AVG/MAX     0.014527/0.014527/0.014527 sec out of 1

  CTDB version

Version of the ctdb protocol used by the node.

  Current time of statistics

Time when the statistics are generated.

This is useful when collecting statistics output periodically for post-processing.

  Statistics collected since

Time when ctdb was started or the last time statistics was reset. The output shows the duration and the timestamp.

  num_clients

Number of processes currently connected to CTDB's unix socket. This includes recovery daemon, ctdb tool and samba processes (smbd, winbindd).

  frozen

1 if the databases are currently frozen, 0 otherwise.

  recovering

1 if recovery is active, 0 otherwise.

  num_recoveries

Number of recoveries since the start of ctdb or since the last statistics reset.

  client_packets_sent

Number of packets sent to client processes via unix domain socket.

  client_packets_recv

Number of packets received from client processes via unix domain socket.

  node_packets_sent

Number of packets sent to the other nodes in the cluster via TCP.

  node_packets_recv

Number of packets received from the other nodes in the cluster via TCP.

  keepalive_packets_sent

Number of keepalive messages sent to other nodes.

CTDB periodically sends keepalive messages to other nodes. See KeepaliveInterval tunable in ctdb-tunables(7) for more details.

  keepalive_packets_recv

Number of keepalive messages received from other nodes.

  node

This section lists various types of messages processed which originated from other nodes via TCP.

req_call

    Number of REQ_CALL messages from the other nodes.

reply_call

    Number of REPLY_CALL messages from the other nodes.

req_dmaster

    Number of REQ_DMASTER messages from the other nodes.

reply_dmaster

    Number of REPLY_DMASTER messages from the other nodes.

reply_error

    Number of REPLY_ERROR messages from the other nodes.

req_message

    Number of REQ_MESSAGE messages from the other nodes.

req_control

    Number of REQ_CONTROL messages from the other nodes.

reply_control

    Number of REPLY_CONTROL messages from the other nodes.

req_tunnel

    Number of REQ_TUNNEL messages from the other nodes.

  client

This section lists various types of messages processed which originated from clients via unix domain socket.

req_call

    Number of REQ_CALL messages from the clients.

req_message

    Number of REQ_MESSAGE messages from the clients.

req_control

    Number of REQ_CONTROL messages from the clients.

req_tunnel

    Number of REQ_TUNNEL messages from the clients.

  timeouts

This section lists timeouts occurred when sending various messages.

call

    Number of timeouts for REQ_CALL messages.

control

    Number of timeouts for REQ_CONTROL messages.

traverse

    Number of timeouts for database traverse operations.

  locks

This section lists locking statistics.

num_calls

    Number of completed lock calls. This includes database locks and record locks.

num_current

    Number of scheduled lock calls. This includes database locks and record locks.

num_pending

    Number of queued lock calls. This includes database locks and record locks.

num_failed

    Number of failed lock calls. This includes database locks and record locks.

  total_calls

Number of req_call messages processed from clients. This number should be same as client --> req_call.

  pending_calls

Number of req_call messages which are currently being processed. This number indicates the number of record migrations in flight.

  childwrite_calls

Number of record update calls. Record update calls are used to update a record under a transaction.

  pending_childwrite_calls

Number of record update calls currently active.

  memory_used

The amount of memory in bytes currently used by CTDB using talloc. This includes all the memory used for CTDB's internal data structures. This does not include the memory mapped TDB databases.

  max_hop_count

The maximum number of hops required for a record migration request to obtain the record. High numbers indicate record contention.

  total_ro_delegations

Number of readonly delegations created.

  total_ro_revokes

Number of readonly delegations that were revoked. The difference between total_ro_revokes and total_ro_delegations gives the number of currently active readonly delegations.

  hop_count_buckets

Distribution of migration requests based on hop counts values. Buckets are 0, < 2, < 4, < 8, < 16, < 32, < 64, < 128, < 256, < 512, < 1024, < 2048, < 4096, < 8192, < 16384, ≥ 16384.

  lock_buckets

Distribution of record lock requests based on time required to obtain locks. Buckets are < 1ms, < 10ms, < 100ms, < 1s, < 2s, < 4s, < 8s, < 16s, < 32s, < 64s, ≥ 64s.

  locks_latency

The minimum, the average and the maximum time (in seconds) required to obtain record locks.

  reclock_ctdbd

The minimum, the average and the maximum time (in seconds) required to check if recovery lock is still held by recovery daemon when recovery mode is changed. This check is done in ctdb daemon.

  reclock_recd

The minimum, the average and the maximum time (in seconds) required to check if recovery lock is still held by recovery daemon during recovery. This check is done in recovery daemon.

  call_latency

The minimum, the average and the maximum time (in seconds) required to process a REQ_CALL message from client. This includes the time required to migrate a record from remote node, if the record is not available on the local node.

  childwrite_latency

Default: 0

The minimum, the average and the maximum time (in seconds) required to update records under a transaction.

DATABASE STATISTICS

CTDB maintains per database statistics about important operations. See the ctdb(1) command dbstatistics for displaying database statistics.

  Example: ctdb dbstatistics notify_index.tdb

    DB Statistics: notify_index.tdb
     ro_delegations                     0
     ro_revokes                         0
     locks
         total                        131
         failed                         0
         current                        0
         pending                        0
     hop_count_buckets: 9890 5454 26 1 0 0 0 0 0 0 0 0 0 0 0 0
     lock_buckets: 4 117 10 0 0 0 0 0 0 0 0 0 0 0 0 0
     locks_latency      MIN/AVG/MAX     0.000683/0.004198/0.014730 sec out of 131
     Num Hot Keys:     3
         Count:7 Key:2f636c75737465726673
         Count:18 Key:2f636c757374657266732f64617461
         Count:7 Key:2f636c757374657266732f646174612f636c69656e7473

  DB Statistics

Name of the database.

  ro_delegations

Number of readonly delegations created in the database.

  ro_revokes

Number of readonly delegations revoked. The difference in ro_delegations and ro_revokes indicates the currently active readonly delegations.

  locks

This section lists locking statistics.

total

    Number of completed lock calls. This includes database locks and record locks.

failed

    Number of failed lock calls. This includes database locks and record locks.

current

    Number of scheduled lock calls. This includes database locks and record locks.

pending

    Number of queued lock calls. This includes database locks and record locks.

  hop_count_buckets

Distribution of migration requests based on hop counts values. Buckets are 0, < 2, < 4, < 8, < 16, < 32, < 64, < 128, < 256, < 512, < 1024, < 2048, < 4096, < 8192, < 16384, ≥ 16384.

  lock_buckets

Distribution of record lock requests based on time required to obtain locks. Buckets are < 1ms, < 10ms, < 100ms, < 1s, < 2s, < 4s, < 8s, < 16s, < 32s, < 64s, ≥ 64s.

  locks_latency

The minimum, the average and the maximum time (in seconds) required to obtain record locks.

  Num Hot Keys

Number of contended records determined by hop count. CTDB keeps track of top 10 hot records and the output shows hex encoded keys for the hot records.

SEE ALSO

ctdb(1), ctdbd(1), ctdb-tunables(7), http://ctdb.samba.org/

AUTHOR

This documentation was written by Amitay Isaacs, Martin Schwenke

COPYRIGHT
Copyright © 2007 Andrew Tridgell, Ronnie Sahlberg

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, see http://www.gnu.org/licenses.