Database Reference
In-Depth Information
Using the
lsof
command, we can list all open files. For example, we can list all
open files for a process ID (PID) as follows:
lsof -p 13241
COMMAND PID USER FD TYPE DEVICE SIZE/
OFF NODE NAME
init 13241 root cwd DIR 225,0
4096 1 /
init 13241 root rtd DIR 225,0
4096 1 /
Stack Size Limit
The stack size limits the number of threads we can have in the Java Virtual Machine
(JVM). If you are seeing an error like the following one:
The stack size specified is too small, Specify at least
228k
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
it means stack size is set too low. The default assigned value is 180K, and as re-
commended by Cassandra, we can set it to 228K by modifying the
Cassandra-
env.sh
file (available under the
conf
folder) like this:
JVM_OPTS="$JVM_OPTS -Xss228k"
Out of Memory Errors
With the massive volume of data processed with Cassandra, sometimes nodes may die
with “out of memory” errors. If you encounter this situation, first check the row cache
and memtable sizes and validate whether they are set at values that are too large. Here,
“too large” simply means they can't fit well in the available memory. If these values
are well below available memory limits, then we should investigate the heap dump and
server and application logs for further information on errors. With Cassandra 1.2.9 on-
wards, many background processes have been moved from on-heap to off-heap pro-
