Tenable Log Correlation Engine Hardware Requirements

The following hardware recommendations for Log Correlation Engine are to be used as a general guide. Enterprise networks can vary in performance, capacity, protocols, and overall activity. Resource requirements to consider for deployments include raw network speed, the size of the network being monitored, and the configuration of the application. Processors, memory, and network cards will be heavily based on the former. Disk space requirements will vary depending on usage based on the amount and length of time data is stored on the system.

The hardware requirements for Log Correlation Engine change based on the number of events being processed.

Estimating Events

The following table provides the estimated average number of events from various sources.

Devices	Number of Estimated Events
1 workstation/laptop	0.5 events/sec
1 web-facing app server	20 events/sec
1 web-facing firewall/IDS/IPS	75 events/sec
1 internal application server (low volume)	5 events/sec
1 internal application server (high volume: IIS, Exchange, AD)	20 events/sec
1 internal network device	2 events/sec

To convert your event rate to bytes per day, Tenable recommends that you multiply your total events/second by 250 bytes/event and multiply by 86,400 seconds/day.

System Specification

The following table specifies the system requirements based on the number of events the Log Correlation Engine server is processing.

Version	Installation scenario	RAM	Processor	Hard disk	Hard disk space
6.x	One Log Correlation Engine server with PostgreSQL processing less than 5,000 events per second	22 GB	8 cores	10,000 to 15,000 RPM HD, or SSD of equiv. IOPS capability, in RAID 0/10 configuration	2.4 x Licensed storage size
	One Log Correlation Engine server with PostgreSQL processing between 5,000 and 20,000 events per second	30 GB	16 cores	15,000 RPM HD, or SSD of equiv. IOPS capability; RAID 0/10 configuration
	One Log Correlation Engine server with PostgreSQL processing greater than 20,000 events per second	58 GB or more	24 or more cores	SSD of IOPS capability at least equiv. to a 15,000 RPM HD; RAID 0/10 configuration

The Log Correlation Engine server requires a minimum of 20 GB of storage space to continue running and storing logs. If less than 1 GB is available, the Log Engine (lced) process will stop gracefully and refuse to store additional logs. The current system disk space is visible on the Health and Status page of the Log Correlation Engine interface.

File System Recommendations

Placing your activeDb on a networked file system (e.g. NFS) will result in inadequate system performance. Tenable recommends that you use EXT3, EXT4, XFS, or ZFS; and that you pay close attention to the mount options. Here are the mount options we suggest using, and the mount options we suggest staying away from:

If your file system is:	It is recommended that you use:	It is not recommended to use:
EXT3, EXT4, XFS	noatime	atime or strictatime or relatime or diratime or No *atime at all.
EXT3	barrier=0	barrier=1
EXT4	barrier=0 or nobarrier	barrier=1 or barrier
XFS	nobarrier	barrier
EXT3, EXT4	data=writeback	data=journal or data=ordered or No data=* at all.
ZFS	atime=off	atime=on or relatime=on or No *atime at all.
ZFS	Hardware-dependent	compression=gzip or compression=gzip-N or compression=zle compress=gzip or compress=gzip-N or compress=zle
ZFS	logbias=throughput	logbias=latency or No logbias at all.
ZFS	primarycache=metadata	primarycache=all or primarycache=none or No primarycache=* at all.
ZFS	Hardware-dependent	recordsize=512 or recordsize=1024 or recordsize=2048 or recordsize=4096