Hello,
We are having a performance issue on 3par
After an upgrade of openshift from 4.10 to 4.12 (k8s 1.23 to 1.24) (rhel 8.4 to 8.6)
we are having high service time and latency on volumes.
After investigating we see that read_ahead_kb has changed from 128kb to 32mb.
Default value on the OS should be 4096kb
But we are having this :
cat /sys/class/block/dm-*/queue/read_ahead_kb
32768
32768
32768
32768
32768
32768
Anyone know how the 3par can change this value ?
- Red Hat Engineering confirmed that the value of read_ahead_kb is determined in the kernel by the underlying storage and the drivers used ; each storage/driver will be specific.
we have CSI driver in the middle :
https://scod.hpedev.io/csi_driver/