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durability-monitor

  • reference
March 16, 2025
+ 12
Provides durability statistics in relation to vBuckets.

Syntax

Request syntax:

cbstats host:11210 [common options] durability-monitor vbid

Description

This command provides durability statistics for the specified vBucket. Note that the vBucket ID must be specified.

In the displayed output, the identifier for each durability statistic begins with the string vb_, followed by the vBucket ID and a colon. For example, for vBucket 1023, the identifier for the high_prepared_seqno statistic is vb_1023:high_prepared_seqno.

For an overview of durability in Couchbase Server, see Durability.

Table 1. Durability Monitor Statistics
Name Description

high_prepared_seqno

The highest sequence number among the prepared durable writes for the vBucket. Prepared durable writes are those in progress, and therefore not yet committed or aborted. The highest sequence number is that of the durable write that has most recently met its durability requirements on the node for the vBucket. The durability requirements depend on the durability level specified for the write. Provided for both active and replica vBuckets.

last_aborted_seqno

The sequence number of the last aborted durable write for the vBucket. Provided for active vBuckets only.

last_committed_seqno

The sequence number of the last committed durable write for the vBucket. Provided for active vBuckets only.

high_completed_seqno

The highest sequence number among the completed durable writes for the vBucket. Completed includes both aborted and committed. Provided for replica vBuckets only.

last_tracked_seqno

The sequence number of the last durable write to be tracked for the vBucket. Provided for active vBuckets only.

num_tracked

The number of durable writes currently being tracked for the vBucket. Provided for active vBuckets only.

replication_chain_First:ns_1@<node-ip-address>:last_ack_seqno

The sequence number of the last prepared durable write that the stated node has acknowledged to the active node. The replication_chain_Second statistic may also appear, during a topology change, such as rebalance. Provided for active vBuckets only.

replication_chain_First:ns_1@<node-ip-address>:last_write_seqno:

The sequence number of the last-written durable write that the stated node has acknowledged to the active node. The replication_chain_Second statistic may also appear, during a topology change, such as rebalance. Provided for active vBuckets only.

state

The state of the vBucket, which can be either active or replica. Provided for both active and replica vBuckets.

For common options, see cbstats.

Examples

The two commands shown below provide output for an active and a replica vBucket, respectively.

/opt/couchbase/bin/cbstats localhost:11210 -u Administrator -p password \
durability-monitor -b travel-sample 112
vb_112:high_prepared_seqno:                                          0
vb_112:last_aborted_seqno:                                           0
vb_112:last_committed_seqno:                                         0
vb_112:last_tracked_seqno:                                           0
vb_112:num_tracked:                                                  0
vb_112:replication_chain_First:ns_1@10.143.192.101:last_ack_seqno:   0
vb_112:replication_chain_First:ns_1@10.143.192.101:last_write_seqno: 0
vb_112:replication_chain_First:ns_1@10.143.192.102:last_ack_seqno:   28
vb_112:replication_chain_First:ns_1@10.143.192.102:last_write_seqno: 0
vb_112:replication_chain_First:size:                                 2
vb_112:state:                                                        active

/opt/couchbase/bin/cbstats localhost:11210 -u Administrator -p password \
durability-monitor -b travel-sample 17
vb_17:high_completed_seqno: 0
vb_17:high_prepared_seqno:  0
vb_17:state:                replica

See Also

An overview of durability is provided in Durability.