# Data Migration Monitoring Metrics

If your DM cluster is deployed using DM-Ansible, the monitoring system is also deployed at the same time. This document describes the monitoring metrics provided by DM-worker.

Note:

Currently, DM-master does not provide monitoring metrics yet.

In the Grafana dashboard, the default name of DM is DM-task.

### overview

overview contains some monitoring metrics of all the DM-worker instances in the currently selected task. The current default alert rule is only for a single DM-worker instance.

Metric name Description Alert Severity level
storage capacity The total storage capacity of the disk occupied by relay logs N/A N/A
storage remain The remaining storage capacity of the disk occupied by relay logs N/A N/A
binlog file gap between master and relay The number of binlog files by which the relay processing unit is behind the upstream master N/A N/A
binlog file gap between master and syncer The number of binlog files by which binlog replication is behind the upstream master N/A N/A
shard lock resolving Whether the current subtask is waiting for sharding DDL replication. A value greater than 0 means that the current subtask is waiting for sharding DDL replication N/A N/A

Metric name Description Alert Severity level

### Relay log

Metric name Description Alert Severity level
storage capacity The storage capacity of the disk occupied by the relay log N/A N/A
storage remain The remaining storage capacity of the disk occupied by the relay log An alert is needed once the value is smaller than 10G critical
process exits with error The relay log encounters an error within the DM-worker and exits Immediate alerts critical
relay log data corruption The number of corrupted relay log files Immediate alerts emergency
fail to read binlog from master The number of errors encountered when the relay log reads the binlog from the upstream MySQL Immediate alerts critical
fail to write relay log The number of errors encountered when the relay log writes the binlog to disks Immediate alerts critical
binlog file index The largest index number of relay log files. For example, “value = 1” indicates “relay-log.000001” N/A N/A
binlog file gap between master and relay The number of binlog files in the relay log that are behind the upstream master An alert occurs when the number of binlog files by which the relay processing unit is behind the upstream master exceeds one (>1) and the condition lasts over 10 minutes critical
binlog pos The write offset of the latest relay log file N/A N/A
read binlog duration The duration that the relay log reads binlog from the upstream MySQL (in seconds) N/A N/A
write relay log duration The duration that the relay log writes binlog into the disks each time (in seconds) N/A N/A
binlog size The size of a single binlog event that the relay log writes into the disks N/A N/A

The following metrics show only when task-mode is in the full or all mode.

Metric name Description Alert Severity level
data file size The total size of the data files (includes the INSERT INTO statement) in the full data imported by the load unit N/A N/A
dump process exits with error The dump unit encounters an error within the DM-worker and exits Immediate alerts critical
load process exits with error The load unit encounters an error within the DM-worker and exits Immediate alerts critical
table count The total number of tables in the full data imported by the load unit N/A N/A
data file count The total number of data files (includes the INSERT INTO statement) in the full data imported by the load unit N/A N/A
latency of execute transaction The latency of executing a transaction by the load unit (in seconds) N/A N/A
latency of query The latency of executing of executing a query by the load unit (in seconds) N/A N/A

### Binlog replication

The following metrics show only when task-mode is in the incremental or all mode.

Metric name Description Alert Severity level
remaining time to sync The predicted remaining time it takes syncer to be completely replicated with the master (in minutes) N/A N/A
replicate lag The latency time it takes to replicate the binlog from master to syncer (in seconds) N/A N/A
process exist with error The binlog replication process encounters an error within the DM-worker and exits Immediate alerts critical
binlog file gap between master and syncer The number of binlog files by which the syncer processing unit is behind the master An alert occurs when the number of binlog files by which the syncer processing unit is behind the master exceeds one (>1) and the condition lasts over 10 minutes critical
binlog file gap between relay and syncer The number of binlog files by which syncer is behind relay An alert occurs when the number of binlog files by which the syncer processing unit is behind the relay processing unit exceeds one (>1) and the condition lasts over 10 minutes critical
binlog event qps The number of binlog events received per unit of time (this number does not include the events that need to be skipped) N/A N/A
skipped binlog event qps The number of binlog events received per unit of time that need to be skipped N/A N/A
cost of binlog event transform The time it takes syncer to parse and transform the binlog into SQL statements (in seconds) N/A N/A
total sqls jobs The number of newly added jobs per unit of time N/A N/A
finished sqls jobs The number of finished jobs per unit of time N/A N/A
execution latency The time it takes syncer to execute the transaction to the downstream (in seconds) N/A N/A
unsynced tables The number of tables that have not received the shard DDL statement in the current subtask N/A N/A
shard lock resolving Whether the current subtask is waiting for the shard DDL lock to be resolved. A value greater than 0 indicates that it is waiting for the shard DDL lock to be resolved N/A N/A

## Instance

In the Grafana dashboard, the default name of an instance is DM-instance.

### Relay log

Metric name Description Alert Severity level
storage capacity The total storage capacity of the disk occupied by the relay log N/A N/A
storage remain The remaining storage capacity within the disk occupied by the relay log An alert occurs once the value is smaller than 10G critical
process exits with error The relay log encounters an error in DM-worker and exits Immediate alerts critical
relay log data corruption The number of corrupted relay logs Immediate alerts emergency
fail to read binlog from master The number of errors encountered when relay log reads the binlog from the upstream MySQL Immediate alerts critical
fail to write relay log The number of errors encountered when the relay log writes the binlog to disks Immediate alerts critical
binlog file index The largest index number of relay log files. For example, “value = 1” indicates “relay-log.000001” N/A N/A
binlog file gap between master and relay The number of binlog files by which the relay processing unit is behind the upstream master An alert occurs when the number of binlog files by which the relay processing unit is behind the upstream master exceeds one (>1) and the condition lasts over 10 minutes critical
binlog pos The write offset of the latest relay log file N/A N/A
read binlog duration The duration that the relay log reads the binlog from the upstream MySQL (in seconds) N/A N/A
write relay log duration The duration that the relay log writes the binlog into the disk each time (in seconds) N/A N/A
binlog size The size of a single binlog event that the relay log writes into the disks N/A N/A