System process queue lengths and Load averages
runq-sz
Run queue length (number of tasks waiting for run time).

plist-sz
Number of tasks in the task list.

ldavg-1
System load average for the last minute. The load average is calculated as the average number of runnable or running tasks (R state), and the number of tasks in uninterruptible sleep (D state) over the specified interval.

ldavg-5
System load average for the past 5 minutes.

ldavg-15
System load average for the past 15 minutes.

Memory utilization statistics
kbmemfree
Amount of free memory available in kilobytes.

kbmemused
Amount of used memory in kilobytes. This does not take into account memory used by the kernel itself.

%memused
Percentage of used memory.

kbbuffers
Amount of memory used as buffers by the kernel in kilobytes.

kbcached
Amount of memory used to cache data by the kernel in kilobytes.

kbcommit
Amount of memory in kilobytes needed for current workload. This is an estimate of how much RAM/swap is needed to guarantee that there never is out of memory.

%commit
Percentage of memory needed for current workload in relation to the total amount of memory (RAM+swap). This number may be greater than 100% because the kernel usually overcommits memory.

Memory statistics
frmpg/s
Number of memory pages freed by the system per second. A negative value represents a number of pages allocated by the system. Note that page has a size of 4 kB or 8 kB according to the machine architecture.

bufpg/s
Number of additional memory pages used as buffers by the system per second. A negative value means fewer pages used as buffers by the system.

campg/s
Number of additional memory pages cached by the system per second. A negative value means fewer pages in the cache.

Swap space utilization statistics
kbswpfree
Amount of free swap space in kilobytes.

kbswpused
Amount of used swap space in kilobytes.

%swpused
Percentage of used swap space.

kbswpcad
Amount of cached swap memory in kilobytes. This is memory that once was swapped out, is swapped back in but still also is in the swap area (if memory is needed it doesn't need to be swapped out again because it is already in the swap area. This saves I/O).

%swpcad
Percentage of cached swap memory in relation to the amount of used swap space.

CPU utilization
%user
Percentage of CPU utilization that occurred while executing at the user level (application). Note that this field includes time spent running virtual processors.

%usr
Percentage of CPU utilization that occurred while executing at the user level (application). Note that this field does NOT include time spent running virtual processors.

%nice
Percentage of CPU utilization that occurred while executing at the user level with nice priority.

%system
Percentage of CPU utilization that occurred while executing at the system level (kernel). Note that this field includes time spent servicing hardware and software interrupts.

%sys
Percentage of CPU utilization that occurred while executing at the system level (kernel). Note that this field does NOT include time spent servicing hardware or software interrupts.

%iowait
Percentage of time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request.

%steal
Percentage of time spent in involuntary wait by the virtual CPU or CPUs while the hypervisor was servicing another virtual processor.

%irq
Percentage of time spent by the CPU or CPUs to service hardware interrupts.

%soft
Percentage of time spent by the CPU or CPUs to service software interrupts.

%guest
Percentage of time spent by the CPU or CPUs to run a virtual processor.

%idle
Percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.
Note: On SMP machines a processor that does not have any activity at all (0.00 for every field) is a disabled (offline) processor.

Task creation and system switching activity
proc/s
Total number of tasks created per second.

cswch/s
Total number of context switches per second.

Swapping statistics
pswpin/s
Total number of swap pages the system brought in per second.

pswpout/s
Total number of swap pages the system brought out per second.

I/O and transfer rate statistics:
tps
Total number of transfers per second that were issued to physical devices. A transfer is an I/O request to a physical device. Multiple logical requests can be combined into a single I/O request to the device. A transfer is of indeterminate size.

rtps
Total number of read requests per second issued to physical devices.

wtps
Total number of write requests per second issued to physical devices.

bread/s
Total amount of data read from the devices in blocks per second. Blocks are equivalent to sectors and therefore have a size of 512 bytes.

bwrtn/s
Total amount of data written to devices in blocks per second.

Activity for each block device ( block devices statistics )
tps
Indicate the number of transfers per second that were issued to the device. Multiple logical requests can be combined into a single I/O request to the device. A transfer is of indeterminate size.

rd_sec/s
Number of sectors read from the device. The size of a sector is 512 bytes.

wr_sec/s
Number of sectors written to the device. The size of a sector is 512 bytes.

avgrq-sz
The average size (in sectors) of the requests that were issued to the device.

avgqu-sz
The average queue length of the requests that were issued to the device.h2. await The average time (in milliseconds) for I/O requests issued to the device to be served. This includes the time spent by the requests in queue and the time spent servicing them.

svctm
The average service time (in milliseconds) for I/O requests that were issued to the device. Warning! Do not trust this field any more. This field will be removed in a future sysstat version.

%util
Percentage of CPU time during which I/O requests were issued to the device (bandwidth utilization for the device). Device saturation occurs when this value is close to 100%.)

Paging statistics
pgpgin/s
Total number of kilobytes the system paged in from disk per second.

pgpgout/s
Total number of kilobytes the system paged out to disk per second.

fault/s
Number of page faults (major + minor) made by the system per second. This is not a count of page faults that generate I/O, because some page faults can be resolved without I/O.

majflt/s
Number of major faults the system has made per second, those which have required loading a memory page from disk.

pgfree/s
Number of pages placed on the free list by the system per second.

pgscank/s
Number of pages scanned by the kswapd daemon per second.

pgscand/s
Number of pages scanned directly per second.

pgsteal/s
Number of pages the system has reclaimed from cache (pagecache and swapcache) per second to satisfy its memory demands.

%vmeff
Calculated as pgsteal / pgscan, this is a metric of the efficiency of page reclaim. If it is near 100% then almost every page coming off the tail of the inactive list is being reaped. If it gets too low (e.g. less than 30%) then the virtual memory is having some difficulty. This field is displayed as zero if no pages have been scanned during the interval of time.

Network DEVICES statistics
rxpck/s
Total number of packets received per second.

txpck/s
Total number of packets transmitted per second.

rxkB/s
Total number of kilobytes received per second.

txkB/s
Total number of kilobytes transmitted per second.

rxcmp/s
Number of compressed packets received per second (for cslip etc.)

txcmp/s
Number of compressed packets transmitted per second.

rxmcst/s
Number of multicast packets received per second.

Network DEVICES ERROR statistics
rxerr/s
Total number of bad packets received per second.

txerr/s
Total number of errors that happened per second while transmitting packets.

coll/s
Number of collisions that happened per second while transmitting packets.

rxdrop/s
Number of received packets dropped per second because of a lack of space in linux buffers.

txdrop/s
Number of transmitted packets dropped per second because of a lack of space in linux buffers.

txcarr/s
Number of carrier-errors that happened per second while transmitting packets.

rxfram/s
Number of frame alignment errors that happened per second on received packets.

rxfifo/s
Number of FIFO overrun errors that happened per second on received packets.

txfifo/s
Number of FIFO overrun errors that happened per second on transmitted packets.

SOCK statistics (IPV4)
totsck
Total number of sockets used by the system.

tcpsck
Number of TCP sockets currently in use.

udpsck
Number of UDP sockets currently in use.

rawsck
Number of RAW sockets currently in use.

ip-frag
Number of IP fragments currently in use.

tcp-tw
Number of TCP sockets in TIME_WAIT state.

IPv4 network traffic Statistics
irec/s
The total number of input datagrams received from interfaces per second, including those received in error [ipInReceives].

fwddgm/s
The number of input datagrams per second, for which this entity was not their final IP destination, as a result of which an attempt was made to find a route to forward them to that final destination [ipForwDatagrams].

idel/s
The total number of input datagrams successfully delivered per second to IP user-protocols (including ICMP) [ipInDelivers].

orq/s
The total number of IP datagrams which local IP user-protocols (including ICMP) supplied per second to IP in requests for transmission [ipOutRequests]. Note that this counter does not include any datagrams counted in fwddgm/s.

asmrq/s
The number of IP fragments received per second which needed to be reassembled at this entity [ipReasmReqds].

asmok/s
The number of IP datagrams successfully re-assembled per second [ipReasmOKs].

fragok/s
The number of IP datagrams that have been successfully fragmented at this entity per second [ipFragOKs].

fragcrt/s
The number of IP datagram fragments that have been generated per second as a result of fragmentation at this entity [ipFragCreates].