Bucket monitoring within the Couchbase Web Console has been updated to show additional detailed information. The following statistic groups are available for Couchbase bucket types.
Summary
The summary section provides a quick overview of the cluster activity. For more information, see Section 6.3.3.1, “Bucket Monitoring — Summary Statistics”.
vBucket Resources
This section provides detailed information on the vBucket resources across the cluster, including the active, replica and pending operations. For more information, see Section 6.3.3.2, “Bucket Monitoring — vBucket Resources”.
Disk Queues
Disk queues show the activity on the backend disk storage used for persistence within a data bucket. The information displayed shows the active, replica and pending activity. For more information, see Section 6.3.3.3, “Bucket Monitoring — Disk Queues”.
TAP Queues
The TAP queues section provides information on the activity within the TAP queues across replication, rebalancing and client activity. For more information, see Section 6.3.3.4, “Bucket Monitoring — TAP Queues”.
Top Keys
This shows a list of the top 10 most actively used keys within the selected data bucket.
For Memcached bucket types, the Memcached static summary is provided. See Section 6.3.3.5, “Bucket Monitoring — Memcached Buckets”.
The summary section is designed to provide a quick overview of the cluster activity. Each graph (or selected graph) shows information based on the currently selected bucket.
The following graph types are available:
ops per second
The total number of operations per second on this bucket.
cache miss ratio
Percentage of reads per second to this bucket which required a read from disk rather than RAM.
creates per sec.
Number of new items created in this bucket per second.
updates per sec.
Number of existing items updated in this bucket per second.
disk reads per sec.
Number of reads per second from disk for this bucket.
temp OOM per second
Number of temporary out-of-memory errors sent to clients for this bucket.
gets per second
Number of get operations per second for this bucket.
sets per second
Number of set/update operations per second for this bucket.
CAS ops per sec.
Number of compare and swap operations per second for this bucket.
deletes per sec.
Number of delete operations per second for this bucket.
items
Item count for this bucket.
disk write queue
Size of the disk write queue for this bucket.
memory used
Couchbase Server 1.8.1 or later
The memory used within this bucket.
high water mark
Couchbase Server 1.8.1 or later
The high water mark for memory usage.
low water mark
Couchbase Server 1.8.1 or later
The low water mark for memory usage.
disk update time
Couchbase Server 1.8.1 or later
The time taken to update the persisted informaiton on disk. This provides an indication of the fragmentation level of the SQLite data files used for persistence.
The vBucket statistics provide information for all vBucket types within the cluster across three different states. Within the statistic display the table of statistics is organized in four columns, showing the Active, Replica and Pending states for each individual statistic. The final column provides the total value for each statistic.
The Active column displays the information for vBuckets within the Active state. The Replica column displays the statistics for vBuckets within the Replica state (i.e. currently being replicated). The Pending columns shows statistics for vBuckets in the Pending state, i.e. while data is being exchanged during rebalancing.
These states are shared across all the following statistics. For example, the graph new items per sec within the Active state column displays the number of new items per second created within the vBuckets that are in the active state.
The individual statistics, one for each state, shown are:
vBuckets
The number of vBuckets within the specified state.
items
Number of items within the vBucket of the specified state.
% resident items
Percentage of items within the vBuckets of the specified state that are resident (in RAM).
new items per second
Number of new items created in vBuckets within the specified state. Note that new items per second is not valid for the Pending state.
ejections per second
Number of items ejected per second within the vBuckets of the specified state.
user data in RAM
Size of user data within vBuckets of the specified state that are resident in RAM.
metadata in RAM
Size of item metadata within the vBuckets of the specified state that are resident in RAM.
The Disk Queues statistics section displays the information for data being placed into the disk queue. Disk queues are used within Couchbase Server to store the information written to RAM on disk for persistence. Information is displayed for each of the disk queue states, Active, Replica and Pending.
The Active column displays the information for the Disk Queues within the Active state. The Replica column displays the statistics for the Disk Queues within the Replica state (i.e. currently being replicated). The Pending columns shows statistics for the disk Queues in the Pending state, i.e. while data is being exchanged during rebalancing.
These states are shared across all the following statistics. For example, the graph fill rate within the Replica state column displays the number of items being put into the replica disk queue for the selected bucket.
The displayed statistics are:
items
The number of items waiting to be written to disk for this bucket for this state.
fill rate
The number of items per second being added to the disk queue for the corresponding state.
drain rate
Number of items actually written to disk from the disk queue for the corresponding state.
average age
The average age of items (in seconds) within the disk queue for the specified state.
The TAP queues statistics are designed to show information about the TAP queue activity, both internally, between cluster nodes and clients. The statistics information is therefore organized as a table with columns showing the statistics for TAP queues used for replication, rebalancing and clients.
The statistics in this section are detailed below:
# tap senders
Number of TAP queues in this bucket for internal (replica), rebalancing or client connections.
# items
Number of items in the corresponding TAP queue for this bucket.
fill rate
Number of items per second being put into the corresponding TAP queue for this bucket.
drain rate
Number of items per second being sent over the corresponding TAP queue connections to this bucket.
back-off rate
Number of back-offs per second received when sending data through the corresponding TAP connection to this bucket.
# backfill remaining
Number of items in the backfill queue for the corresponding TAP connection for this bucket.
# remaining on disk
Number of items still on disk that need to be loaded to service the TAP connection to this bucket.
For Memcached buckets a separate suite of Memcached-specific statistics are displayed.
The Memcached statistics are:
Operations per sec.
Total operations per second serviced by this bucket
Hit Ratio %
Percentage of get requests served with data from this bucket
Memory bytes used
Total amount of RAM used by this bucket
Items count
Number of items stored in this bucket
RAM evictions per sec.
Number of items per second evicted from this bucket
Sets per sec.
Number of set operations serviced by this bucket
Gets per sec.
Number of get operations serviced by this bucket
Net. bytes TX per sec
Number of bytes per second sent from this bucket
Net. bytes RX per sec.
Number of bytes per second sent into this bucket
Get hits per sec.
Number of get operations per second for data that this bucket contains
Delete hits per sec.
Number of delete operations per second for data that this bucket contains
Incr hits per sec.
Number of increment operations per second for data that this bucket contains
Decr hits per sec.
Number of decrement operations per second for data that this bucket contains
Delete misses per sec.
Number of delete operations per second for data that this bucket does not contain
Decr misses per sec.
Number of decr operations per second for data that this bucket does not contain
Get Misses per sec.
Number of get operations per second for data that this bucket does not contain
Incr misses per sec.
Number of increment operations per second for data that this bucket does not contain
CAS ops per sec.
Number of CAS operations per second for data that this bucket contains
CAS badval per sec.
Number of CAS operations per second using an incorrect CAS ID for data that this bucket contains
CAS misses per sec.
Number of CAS operations per second for data that this bucket does not contain