I have created two cluster nodes (db1 and db2) running CentOS 7.6, Couchbase Community Server Edition 6.0.0 build 1693
Through code I create the same indexes on both clusters (using the Java SDK). However, I have now discovered that there are some major differences on the two servers’ use of disk.
The database takes up 2.15 GB on db1 and 2.23 GB on db2.
However, in the directory:
opt/couchbase/var/lib/couchbase/data there are some major differences. On db2 this directory has a size of 4.11 KB whereas on db1 it takes up 2.34 GB!!
On db2 there is only one directory in
data which is called
.delete - and it is empty. On db1 there are several directories in addition to that one, namely: @2i (767 MB), @fts (32 bytes), @indexes (66 MB), and data (1.53 GB).
In the data directory there are many files named like: 0.couch.16, 1.couch.15, 10.couch.13, etc.
So this leads me to a couple of questions:
- Why is there such a difference on two nodes that are clustered?
- Why do the @-directories not show up on both servers?
- What is the data in the lowest level data directory which makes the biggest difference?
Sometimes I see the db2 server get quite unresponsive (like not being able to open the Couchbase console - or even Webmin or SSH to the server). Could there be any connection to the above differences? A reboot normally resolves the issue (or rather clears the symptom)
The above data are in a test environment - so no stress here. However, I have a similar production environment (without the size differences) - and therefore I’m quite curious to understand what’s going on in the test environment so I can be prepared if something like this should hit the production environment…