Add the disk.dev.scheduler metric, which reports which I/O scheduler is
in use by each device. This is simple to figure out in recent kernels,
using /sys/block//queue/scheduler, but not so easy in older kernels
where we need to sniff around the iosched parameter files to intuit it.
Importantly, RHEL5 (and I suspect also SLES10) seem to provide no other
way to tell which scheduler is in use (it can only be adjusted via the
kernel boot parameters - ugh!).
Add the disk.dev.scheduler metric, which reports which I/O scheduler is
in use by each device. This is simple to figure out in recent kernels,
using /sys/block//queue/scheduler, but not so easy in older kernels
where we need to sniff around the iosched parameter files to intuit it.
Importantly, RHEL5 (and I suspect also SLES10) seem to provide no other
way to tell which scheduler is in use (it can only be adjusted via the
kernel boot parameters - ugh!).