Database Reference
In-Depth Information
recent hit rate, 0 save period
in seconds
Most of the items in this output are fairly straightforward. There are a few nu-
ances that should be covered.
Load
references the size of the data on disk. The
Generation No
field is a status report from the Gossip protocol. The number is
the time that the most recent heartbeat was received by this node. The
Rack
field
is important only if you are using a snitch that makes use of multiple data centers
and racks.
Ring Information
The most common command you will probably find yourself running is
node-
tool ring
. This command presents all the nodes in the cluster and their status
from the perspective of the node being queried. Let's take a look at a healthy and
well-balanced three-node cluster (see
Listing 7.4
)
.
Listing 7.4
Healthy Three-Node Ring
$ nodetool ring
Address
DC
Rack
Status State
Load
Effective-
ership Token
10.100.0.100
us-east
1a
Up
Normal
501.29 MB 33.33% 0
10.100.1.110
us-east
1a
Up
Normal
441.13 MB 33.33% 5671372782015641
10.100.2.120
us-east
1a
Up
Normal
499.29 MB 33.33% 1134274556403128