HPVM in RX6600 - How to configure multipathing with Veritas

[MJA_1]

I am new in HPVM. I have project to configure two VM in rx6600 like the following configuration
Partition #1: 2 CPU \ 24 GB RAM \ 300 GB SAN attached drive
Partition #2: 2 CPU \ 24 GB RAM \ 300 GB SAN attached drive

Q1)If VM host has 48GB RAM and 2 VM Guest require 24GB and 24 GB then how VM host can allow to share all 48GB to its both VM?
Q2)I will assign 300GB Fiber sanLuns to both VM Guest to install oracle dataabe. How I can configure veritas multipathing for this san space either from VM host or VM Guest. If you do have any best practice doc for configuring multipathing, it will be very helpful.

Thanks .. MJ

[Geoff Wild]

You can't allocate more ram then you have - nor the exact amount you have.

Also - some is reserved for the host as well...

Example - I had 48 GB of ram - but could only allocate 44 GB.


To be honest - I would allocate 20 GB to each vm. Save 8 GB for the host.

You also need to allocate that much swap to the hosts as well.


Multipathing is done at the host level - as all I/O goes through it anyways.

Read the Integrity Virtual Machines docs:

http://docs.hp.com/en/vse.html#HP%20Integrity%20Virtual%20Machines

Rgds...Geoff

[Torsten.]

From the guest point of view everything is virtual, but the host needs to have real resources.

Note the memory calculation formula in the manual.

To check you can run

# hpvmstatus -m
and watch the "Available memory" value.

Multipathing is done on the host level managed by the volume manager (just like on a "normal" system), just create a logical volume and provide this as a virtual drive to the guests.

[MJA_1]

Thanks Geoff Wild and Torsten.
So if I want to maintain multipathing of san space which I will assign to each VM Guest, I will need to create a logical volume and provide these as virtual drive to guest.
Like I have 3 Luns as below
c0t0d0s2 auto:hpdisk rootdisk01 rootdg online
c0t1d0s2 auto:hpdisk online
c1t0d1 auto: online
c1t0d2 auto: online
Then I will create diskgroup as below
c0t0d0s2 auto:hpdisk rootdisk01 rootdg online
c0t1d0s2 auto:hpdisk rootmirror rootdg online
c1t0d1 auto:cdsdisk sandg101 sandg1 online
c1t0d2 auto:cdsdisk sandg201 sandg2 online
and then the following logical volumes will be provided as virtual drives to guests.
/dev/vx/dsk/sandg1/vol1 >>>300GB
/dev/vx/dsk/sandg2/vol2 >>>300GB


and these virtual drives in guest will be like scsi drives and when I will see ioscan in guests it will show in cxtxdx format and this way these disks will be multipathing.
Right? Please confirm

[Torsten.]

You are right, more or less.

Multipathing is done by VxVM at the host in your setup - so the host will manage the pathes to the LUN.
The guest will not know anything about this.

I think you will get more details with

# vxdisk list sandg1

[MJA_1]

let me extend this with one more scenario.
Instead of veritas volume if I want to give raw disk to VM Guest like /dev/rdsk/c0t1d1 then what will be the options for multipathing, Can I use veritas dmp or I will need to use securepath/autopath or pvlinks?
Please advise - Thanks

[Torsten.]

PVLINKS is a feature of LVM.

DMP is a feature of VxVM.

A "raw" disk is not under a volume manager control, so you cannot use a VM feature with a raw disk.

You need to have a special multipathing software (e.g. autopath) for this.

[MJA_1]

Thanks a lot, I got all answers about multipathing in VM Hosts.

[Torsten.]

Please read this too:

http://forums11.itrc.hp.com/service/forums/helptips.do?#33

Have fun!

[Beksinski]

I was able to configure a DMP device from a LUN with 4 paths, and then pass in the raw DMP device (/dev/vx/rdmp/cXtYdZ) in as a disk to the VM. Everything seems to work just as one would expect.

This is on a test system, and I am trying to find out of this is a supported configuration.

[Duncan Edmonstone]

Although it is possible to configure a DMP device as a backing store in a HPVM, it isn't supported. Your supported choices are:

For AVIO

- a raw disk (with or without a multi-pathing solution such as HP Secure Path or EMC Power Path)
- a Logical volume (with or without LVM)

for non-AVIO

- a raw disk (with or without a multi-pathing solution such as HP Secure Path or EMC Power Path)
- a Logical volume (with or without LVM)
- a VxVM volume (with or without DMP), but NOT a DMP raw disk itself
- a file in a filesystem

HTH

Duncan

[Eric SAUBIGNAC]

Bonjour,

missed this thread :-( Anyway

For memory allocation you have already opened a thread "How much memory and swap space I should have for VM Hosts" http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1198245 IMHO you had some answers there ... but there are not yet points assigned. Maybe you forgot them ?

In the same idea "How I can Assign 2 CPU in both Guests if I have 4 CPUs RX6600" http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1198243

and a more recent thread "After rebooting hp-ux in vm guest, it is not starting os" http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1208978

As underlined by Torsten you are supposed to give points, even 0

Regards

Eric

[Duncan Edmonstone]

oops my last post should have read:

Although it is possible to configure a DMP device as a backing store in a HPVM, it isn't supported. Your supported choices are:

For AVIO

- a raw disk (with or without a multi-pathing solution such as HP Secure Path or EMC Power Path)
- a Logical volume (with or without PVlinks)

for non-AVIO

- a raw disk (with or without a multi-pathing solution such as HP Secure Path or EMC Power Path)
- a Logical volume (with or without PVlinks)
- a VxVM volume (with or without DMP), but NOT a DMP raw disk itself
- a file in a filesystem

HTH

Duncan

[Beksinski]

Thanks Duncan. Just a few hours after I posted that I found that that is indeed the case. However, I didn't know that VxVM was not supported with AVIO. I'll bring that up with our assigned sales/architect guy (as he suggested using VxVM and knew we were using AVIO!).

It seems we are running exactly the only IVM configuration that is not supported with any load balanced storage - AVIO, Hitachi Storage, and IVM 3.5. AVIO doesn't work with VxVM, and HDLM is not supported with IVM 3.5.

We'll be pushing on both vendors :)

[Steve Jones_5]

Could someone say why 'raw' DMP devices (ie /dev/vx/rdmp/cXtYdZ) are not supported as VM disks, as this arrangement certainly appears to work ok in my test environment. Is there a sound technical reason for this, or is it a 'revenue' thing?

[Duncan Edmonstone]

Steve,

Cos Symantec don't support it:

http://docs.hp.com/en/T2767-90114/ch08s04.html

I expect this is a 'not tested' scenario. Unlike other multi-pathing solutions like HP Secure Path or EMC PowerPath, DMP is designed for one application only - VxVM, and I expect Symantec don't intend for anything apart from VxVM to use it - they therefore probably reserve the right to chnage the interface between DMP and VxVM, and if you go using it for something else something might get broken.

That's my best guess of the situation - regardless of whether it works or not it isn't supported so use at your own risk.

All these issues will hopefully go away when we finally get to use 11iv3 as the VM host and use native MPIO (hopefully later this year).

HTH

Duncan