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EMC PowerPath on Linux and Net-SNMP
Hi all,
I am new to PowerPath on Linux and this forum. I am trying to determine IOPS on a Linux database server and Net-SNMP is reporting back 8 devices from a VNX5300, each "pair" having a letter and a matching one ending in 1.
.1.3.6.1.4.1.2021.13.15.1.1.2.67 = STRING: emcpowerd
.1.3.6.1.4.1.2021.13.15.1.1.2.68 = STRING: emcpowerd1
.1.3.6.1.4.1.2021.13.15.1.1.2.69 = STRING: emcpowerg
.1.3.6.1.4.1.2021.13.15.1.1.2.70 = STRING: emcpowerg1
.1.3.6.1.4.1.2021.13.15.1.1.2.71 = STRING: emcpowere
.1.3.6.1.4.1.2021.13.15.1.1.2.72 = STRING: emcpowere1
.1.3.6.1.4.1.2021.13.15.1.1.2.73 = STRING: emcpowerf
.1.3.6.1.4.1.2021.13.15.1.1.2.74 = STRING: emcpowerf1
Each of these has it's own counters and they are not exact but are very close. I wasn't sure if each of these is legit and load balancing is in play or if this is just a by-product of how PowerPath works. I do know fdisk doesn't show any partitions for the devices ending in 1, so that's where I am most confused.
Any help or guidance appreciated.
- Kyle
umichklewis
1.2K Posts
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April 12th, 2016 14:00
Correct - you'll want to focus on IOPs to devices under LVM control. Collect the SNMP performance data from those four devices under LVM control.
Let us know if that helps!
Karl
KyleTucker
4 Posts
0
April 11th, 2016 12:00
# powermt display dev=all
Pseudo name=emcpowerd
CLARiiON ID=APMxxxxxxxxxxx [localhost]
Logical device ID=600601607CF22E005A1E819A0772E111 [localhost_Datafiles2]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0;
Owner: default=SP B, current=SP B Array failover mode: 4
==============================================================================
--------------- Host --------------- - Stor - -- I/O Path -- -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
3 qla2xxx sdg SP A1 active alive 0 0
3 qla2xxx sdk SP B1 active alive 0 0
4 qla2xxx sdq SP A0 active alive 0 0
4 qla2xxx sdu SP B0 active alive 0 0
Pseudo name=emcpowerg
CLARiiON ID=APMxxxxxxxxxxx [localhost]
Logical device ID=600601607CF22E0084BD035B06CAE211 [localhost_Datafiles3]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0;
Owner: default=SP B, current=SP B Array failover mode: 4
==============================================================================
--------------- Host --------------- - Stor - -- I/O Path -- -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
3 qla2xxx sdh SP A1 active alive 0 0
3 qla2xxx sdl SP B1 active alive 0 0
4 qla2xxx sdr SP A0 active alive 0 0
4 qla2xxx sdv SP B0 active alive 0 0
Pseudo name=emcpowere
CLARiiON ID=APMxxxxxxxxxxx [localhost]
Logical device ID=600601607CF22E009E434BF0A86FE111 [localhost_Archives]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0;
Owner: default=SP A, current=SP A Array failover mode: 4
==============================================================================
--------------- Host --------------- - Stor - -- I/O Path -- -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
3 qla2xxx sdf SP A1 active alive 0 0
3 qla2xxx sdj SP B1 active alive 0 0
4 qla2xxx sdp SP A0 active alive 0 0
4 qla2xxx sdt SP B0 active alive 0 0
Pseudo name=emcpowerf
CLARiiON ID=APMxxxxxxxxxxx [localhost]
Logical device ID=600601607CF22E00F86C10EB2172E111 [localhost_Datafiles1]
state=alive; policy=CLAROpt; priority=0; queued-IOs=2;
Owner: default=SP A, current=SP A Array failover mode: 4
==============================================================================
--------------- Host --------------- - Stor - -- I/O Path -- -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
3 qla2xxx sde SP A1 active alive 1 0
3 qla2xxx sdi SP B1 active alive 0 0
umichklewis
1.2K Posts
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April 11th, 2016 12:00
Can you print the output from "powermt display dev=all"?
Thanks!
KyleTucker
4 Posts
0
April 12th, 2016 08:00
Sorry, yes it is LVM. And pvdisplay shows the "1" devices as the physical volumes.
# pvdisplay | grep emcp
PV Name /dev/emcpowerg1
PV Name /dev/emcpowerf1
PV Name /dev/emcpowere1
PV Name /dev/emcpowerd1
So I should only be using the counters from these devices then - not all eight - so my IOPS is actually half what is being picked up by PRTG via Net-SNMP. Is that correct?
umichklewis
1.2K Posts
0
April 12th, 2016 08:00
At first glance, it looks like you're using PowerPath with LVM. emcpowerd is the block (physical) device and emcpowerd1 should be the logical device under LVM control. Output from 'vgdisplay' should help confirm this. The I/Os will not quite match, because Linux is sending certain low-level SCSI primitives to the block device and LVM is sending other commands to the logical device.
Let us know if that helps!
Karl
KyleTucker
4 Posts
1
April 14th, 2016 05:00
This was very helpful. Thanks so much!