HPE EVA Storage

OS level device management with EVA active/active

 
klb
Valued Contributor

OS level device management with EVA active/active


In my environment:

Each LUN presented to my HPUX host has 32 paths:

4(hba ports)x 2(controller A/B) x 4(controller switch ports ) = 32.

I can use the "first" device file for a given LUN in my LVM configuration and autopath will manage which actual device file is used as well as do load balancing and such.

All fine and well, but I come from an active/passive environment where all those extra device files ( essentially disks ) are hidden and therefore not causing confusion. This also lends itself well to easy, intuative VG/LV management and I/O performance monitoring.

I also am partial to building a series of smallish LUNs as opposed to building few really large ones ( i.e. keep the LUNs at 50-200GB ).

This will leave me with many hundreds of entries in /dev/dsk /dev/rdsk.

What are the best practices with respect to the above and in terms of LVM configuration?

Can we hide the multitude of devices somehow like SecurePath(active/passive) does?

Are PVlinks useful in a non-boot VG?

Any other reason I might want to use PVLinks?

Thank you,

-klb




8 REPLIES 8
Torsten.
Acclaimed Contributor

Re: OS level device management with EVA active/active

IMHO 32 links are a bit too much. I would reduce them via LUN presentation in command view.

I assume you are not using 11.31.

Hope this helps!
Regards
Torsten.

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klb
Valued Contributor

Re: OS level device management with EVA active/active


I agree 32 seems excessive. Not sure I can reduce them via presentation. The only way I can reduce it AFAIK is either

1) reduce controller connections to the switch

2) reduce HBA connections to the switch.

3) some funky zoning to do the same as either or both 1) and 2).

Not using 11.31.
Torsten.
Acclaimed Contributor

Re: OS level device management with EVA active/active

Well, I have a system used for HPVM virtualization with 16 FC ports. Can you imagine the number of links if I would present every LUN to every port?

So I present let's say LUN1 to servers port 1,2 ; LUN2 to servers port 3,4 and so on.

This reduces the number of links dramatically.

Hope this helps!
Regards
Torsten.

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klb
Valued Contributor

Re: OS level device management with EVA active/active


Am I missing something? I don't see where I can present to a particular host port. I can edit which ports are defined for a host, but that's system wide.

Under presentation, the only option is to select the host to which the vdisk is to be presented.

This in CV 9.0.

Maybe you're adding the same host multiple times, each with a different set of ports?

Isn't it better to distribute the I/O load across all available HBA ports?
Torsten.
Acclaimed Contributor

Re: OS level device management with EVA active/active

As said, IMHO 32 pathes are too much.

I think it is better to access a LUN or a subset of LUNs via less pathes, so you have less LUNs per path.

The idea is correct, you can create several groups of ports, e.g.

serverA_group01 (as a host)
port1
port2

serverA_group02 (as a host)
port3
port4

...


You should assign unique LUN numbers now manually, because commandview is not aware that all ports belong to a single host.

Hope this helps!
Regards
Torsten.

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Torsten.
Acclaimed Contributor

Re: OS level device management with EVA active/active

... but the best solution would be to use hp-ux 11.31.

1 LUN = 1 device file

Hope this helps!
Regards
Torsten.

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Steven Clementi
Honored Contributor

Re: OS level device management with EVA active/active

Are you sure you have 32 paths? and not 16?

Are your controllers and hba's all connected to the same SAN Fabric? or separate fabrics?


Steven
Steven Clementi
HP Master ASE, Storage, Servers, and Clustering
MCSE (NT 4.0, W2K, W2K3)
VCP (ESX2, Vi3, vSphere4, vSphere5, vSphere 6.x)
RHCE
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klb
Valued Contributor

Re: OS level device management with EVA active/active

> Are you sure you have 32 paths? and not 16?

> Are your controllers and hba's all connected to the same SAN Fabric? or separate fabrics?

Yes, there are 32 valid paths to each LUN, however only 16 are in use as only one controller accesses the LUN at a time.

Only one Fabric is defined I think as there is only one switch.

Any ideas how I can make this more managable?

Thanks,

-klb