For some reason, my locally installed snmp daemon decided to renumber the elements in the hrStorageTable, meaning all the attached disks were being either misreported or just plain dropped from my graphs (/mrtg/blue/index.html). Not that the new numbering doesn’t make sense but I didn’t know this was going to happen.
How to discover and fix it? snmptable is your friend. Any MIB element that is included in a table can be displayed with the entire table, making it easy to see what’s available for monitoring.
As shown here, the memory used by the kernel is listed first, followed by the disks. The disks were numbered starting at 1 before . . . . .
[/www/mrtg/blue]# snmptable -cblue hrStorageTable SNMP table: HOST-RESOURCES-MIB::hrStorageTable hrStorageIndex hrStorageType hrStorageDescr hrStorageAllocationUnits hrStorageSize hrStorageUsed hrStorageAllocationFailures 1 HOST-RESOURCES-TYPES::hrStorageOther Memory Buffers 256 Bytes ? 192 0 2 HOST-RESOURCES-TYPES::hrStorageRam Real Memory 4096 Bytes ? 3241 ? 3 HOST-RESOURCES-TYPES::hrStorageVirtualMemory Swap Space 4096 Bytes ? 19625 ? 4 HOST-RESOURCES-TYPES::hrStorageFixedDisk / 1024 Bytes ? 83592 ? 5 HOST-RESOURCES-TYPES::hrStorageFixedDisk /usr 1024 Bytes ? 3639961 ? 6 HOST-RESOURCES-TYPES::hrStorageFixedDisk /var 1024 Bytes ? 8015 ? 7 HOST-RESOURCES-TYPES::hrStorageFixedDisk /proc 4096 Bytes ? 1 ? 8 HOST-RESOURCES-TYPES::hrStorageFixedDisk /usr/ports 512 Bytes ? 35548516 ?