Slow backups due to high latency on LUNs
Applies to
- SAN
- ONTAP 9
- Red Hat Enterprise Linux (RHEL) 6.7
Issue
- Latency on the LUNs show peaking to 50ms on during backups
- Volume/LUN on one node is accessed by its partner node
multipath -ll
from Linux host shows '0' for a hardware handler and paths are not grouped by priority
[root@linux ~]# multipath -ll
mpathaf (3600a09803831457544245248xxxxxxxx) dm-8 NETAPP,LUN C-Mode
size=500G features='0' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| `- 12:0:0:8 sdh 8:112 active ready running
|-+- policy='round-robin 0' prio=1 status=enabled
| `- 12:0:1:8 sdo 8:224 active ready running
|-+- policy='round-robin 0' prio=1 status=enabled
| `- 12:0:2:8 sdv 65:80 active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
`- 12:0:3:8 sdac 65:192 active ready running