Full MPIO and preferred Path / mode in command view

[Steve Meier]

Hi all,

I am after some info on the best settings for Operating systems
Windows and Linux Rhel .
The reason I ask is we are updating our eva 5000 from 3028 (active/passive) to vcs 4.x (active/active)..

We are going from mpio basic 1.02 on windows to full dsm.
And linux....well I am not sure as I am not linux admin. The linux servers are all qloigc cards in hp blades (c7000 chasis) bl460's.

I want a better understanding of the off the relationship between the load balancing on the hosts and the command view settings.
Cheers
Steve

[IBaltay]

Hi,
1. in active/passive configuration the EVA storage load balancing is used (symmetric load balancing - set preferred path) to balance the VDISKs for the hosts.
2. MPIO is using the assymetric load balancing (ALUA - assymetric logical unit access and its subset ALB - Adaptive load balance). In this method the Set preffered path is set to NONE and the whole VDISK load balancing is driven by the host which is thus requesting the EVA master controller directly without involving the second (proxy) controller...
http://www.scribd.com/doc/2233504/EVA-Overview
(slides 44-48)

[Steve Meier]

Thanks but I was more after information like.
FOR WINDOWS
----------
1) Should we hard set a path in the mpio DSM on each Host ?
2) what Load balancing Policy should we use on the host
3) Do we need to set a "perferred Path/mode" in commadn view to match the path in windows.

Part of the reason asking is it has been suggested to manually distribute the LUNS across our eva 5000 to help lower the risk of mirror port congestion issues between the eva 5000 controllers.

The same questions are applicable also to Linux.
Cheers
Steve

[IBaltay]

Hi,

WINDOWS
----------
1) you should set the MPIO LB
2) usualy SQST
3) if MPIO is used then NONE instead of the set preferred Path is used

MPIO uses ALB -> the host is managing the communication directly with the master controller.

LINUX
1)- 3)
a) you should use qlogic multipath
see this tread pls:
http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1217422641476+28353475&threadId=1161770

b) you should also use the LVM2 for additional striping/loadbalancing

[Patrice Bourdon]

Hi IBaltay,javascript:postAnswerSubmit('submit');
in same subject, i searxh a way to force a windows 2003 sp2 server to use a specific hba card (dsm3 and dsm manager 3 installed).
This server has a 2Gb/s and a 4 Gb/s hba card (bought separately in time...), of course i prefer it uses 4 Gb/S hba card.
How can i fix the path, as i can do it with AIX servers ?
Prefered path in CV is for choosing a controller for LUN, i want to choos the hba card...

TIA

PAt

[IBaltay]

Hi,
maybe this doc can help:
http://download.microsoft.com/download/3/0/4/304083f1-11e7-44d9-92b9-2f3cdbf01048/mpio.doc

[PB75]

Hello All,

I'm trying to get the MPIO Full "ALB" Feature to work probably.

My Test Server uses the following config:
- I set the Presentation Settings of the vdisks in Command View to "Path B-Failover only".
- In MPIO Manager the Devices are set to "Load Balance SQST" and ALB is enabled.

In my understanding with this settings als traffic should be directed only to the master controller (Controller B). If I refresh the View in MPIO Manager, I see constantly changing Paths (B-T-L). There are all Paths used (also the ones to the Non-Master Controller). There are also all Paths marked as "active"
I tried also to set the "preferred Path" in Command View to "No preferrence", it does not change the behavior of the traffic flow. There are still all EVA Ports used.

I use a EVA8100 and MPIO V3.00.00

does anybody have an idea how to get "real ALB" and get the Server talking only to the Master Controller?

regards
Patrick

[Uwe Zessin]

Does the server have an FC port which does not 'see' the EVA at all?
There is a documented 'restriction' (I call it a bug) in the V2 MPIO which causes it to use all controller ports even if you enable ALB. I did not have time to check if V3 has the same bug, errr, 'restriction'.

> ... Master Controller ...

ALB should restrict the I/O to the controller which is 'owning' the virtual disk - that is not always the Master Controller.

[IBaltay]

the Microsoft MPIO ALUA/ALB is briefly described here:
http://www.scribd.com/doc/2233504/EVA-Overview
slide 47, 48.

some details can be gotten also from e.g. the HP-UX 11.31 native MPIO document...
http://docs.hp.com/en/native-multi-pathing/native_multipathing_wp_AR0803.pdf

[IBaltay]

the Microsoft MPIO ALUA/ALB is briefly described here:
http://www.scribd.com/doc/2233504/EVA-Overview
slide 47, 48.

some details can be got also from e.g. the HP-UX 11.31 native MPIO document...
http://docs.hp.com/en/native-multi-pathing/native_multipathing_wp_AR0803.pdf

[PB75]

thanks for your information

The server can see the EVA over all FC Ports. I tried several different configurations (disabling one FC Port, etc.) The result is always the same: if load balancing is activated and ALB enabled, the server uses all available links for transmitting data. It does not only communicate with the Vdisk-owning Controller.

I have no more ideas at the moment.

[IBaltay]

Hi,
you could try the
a) linux HBA driver static load balancing feature and at the same time
b) set preferred path staticaly on the EVA even in Active/Active firmware

The method of host HBA LVM manual balancing and at the same the EVA controllers static alternating the controller a and b (master)(like with HP-UX PVlinks), should give you almost as good performance as the ALB...

[IBaltay]

The only time not optimized and "not hiting the master controller" is the time in case of the failure of the primary LVM link, because the alternative link automatically goes to the other controller which is proxy.
But as soon as the first is repaired it should automaticaly failback to it...

[PB75]

is the "Linux hba driver static load balancing feature" also available on windows?

I have only Windows Server 2003 in use. If I set MPIO to "set load balance none", the Server communicates only with one EVA FC-Port and the other ports are listed with status "available".

[IBaltay]

the above mention idea is the manual host hba and eva front ports balancing method via e.g. the HP-UX pvlinks (LVM). Unfortunately Windows does not have LVM :-(. But nevertheless, the Windows MPIO ALB goes to both EVA controllers even though only one controller is the master controller. Internally if the load on the proxy controller reaches the 51% it automaticaly becomes the master controller.
In here:
http://www.asac.as/web/upload/ponencias/HP-EVA.pdf
the page 13 shows the numer of host ports/mirror ports/device porst (controller to disks). From this you can see that the newer EVAs has twice as mirror ports and that EVA5000 has quite powerfull back-end (8 device ports/4 loop switches like the EVA 8x00)

[Carlos ROjas_3]

Thanks,
Very good solution.

[Oxiel Contreras]

Thank you.

Good documentation, and solved several doubts.