Increasing Hard Drive Space and Not receiving constant data

Hello All:

Need advise on increasing the hard drive on a running system. I have recently installed ROCK NSM on a VM in ESXi host.

I have a feeling i have allocated very small hard drive space to the Rock NSM system ,getting few glitches in over all system performance and others. Specially not receiving constant data on bro. Example i am unable to any see any data in last 15 mins but there is data available in last 2 hours.

As a first step i want to increase the hard drive space i think this may help me in getting the constant data stream. I am very new to NSM your advice is highly appreciated.

Following is the my available hard drive space

[admin@rocknsm ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rocknsm-root 44G 40G 4.9G 90% /
devtmpfs 6.9G 0 6.9G 0% /dev
tmpfs 6.9G 0 6.9G 0% /dev/shm
tmpfs 6.9G 679M 6.2G 10% /run
tmpfs 6.9G 0 6.9G 0% /sys/fs/cgroup
/dev/sda1 1014M 146M 869M 15% /boot
tmpfs 1.4G 0 1.4G 0% /run/user/1000
tmpfs 1.4G 0 1.4G 0% /run/user/994