UCD-SNMP-MIB :: memSysAvail

MIB Reference — IPNetwork Monitor · Updated September 14, 2026

All MIBsUCD-SNMP-MIBmemSysAvail

memSysAvail

Module: UCD-SNMP-MIB

OID (symbolic): UCD-SNMP-MIB::memSysAvail

OID (numeric): 1.3.6.1.4.1.2021.4.27

Node type: OBJECT-TYPE

Type: CounterBasedGauge64

Access: read-only

Description: The total amount of available memory, which is an estimate of how much memory is available for starting new applications, without swapping.

This object will not be implemented on hosts where the underlying operating system does not explicitly identify memory as specifically reserved for this purpose.

What is memSysAvail?

This OID reports an estimate, in kilobytes, of how much memory is available for starting new applications without triggering swapping, on hosts that track this figure explicitly. An admin uses it as a more realistic headroom number than raw free memory, since it can account for reclaimable cache.

Examples

Walk all instances (SNMPv2c):

snmpwalk -v2c -c public <target> 1.3.6.1.4.1.2021.4.27
snmpwalk -v2c -c public <target> UCD-SNMP-MIB::memSysAvail

Get a specific instance (index 1):

snmpget -v2c -c public <target> 1.3.6.1.4.1.2021.4.27.1
snmpget -v2c -c public <target> UCD-SNMP-MIB::memSysAvail.1

SNMPv3 example:

snmpget -v3 -l authPriv -u snmpv3-user -a SHA -A "AuthPassword1" -x AES -X "PrivPassword1" <target> memSysAvail.1

Start monitoring Unix/Linux servers running the Net-SNMP (net-snmp/snmpd) agent (CPU/memory/disk/process-table status) with a free 30-day trial of IPNetwork Monitor. Create custom SNMP monitor using the UCD-SNMP-MIB::memSysAvail OID value, configure state conditions and alerts, and monitor any Unix/Linux servers running the Net-SNMP (net-snmp/snmpd) agent (CPU/memory/disk/process-table status) from a single console.

OID Breakdown

Upper-level ancestors (6 from the standard OID tree / other modules)
Numeric OIDNameModule
1isoLANART-AGENT
1.3orgAirPair-MIB
1.3.6dodAirPair-MIB
1.3.6.1internetAirPair-MIB
1.3.6.1.4privateAirPair-MIB
1.3.6.1.4.1enterprisesAirPair-MIB
Numeric OIDNameModule
1.3.6.1.4.1.2021ucdavisUCD-SNMP-MIB
1.3.6.1.4.1.2021.4memoryUCD-SNMP-MIB
1.3.6.1.4.1.2021.4.27memSysAvailUCD-SNMP-MIB