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Passing HW RAID Volume Direct to VM?


Rukah
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Sorry in advance if I am understanding this wrong...

 

I have a HW RAID Controller (P410) and have created 2 arrays (a 80gb RAID1 and a 4TB RAID5). I have setup ESXI 5.1 (N54L) and am storing all my VM's on the 80GB RAID1 Array (Booting from a small USB Drive) - Everything is working smoothly.

 

Now, here is where I am lost... I want to pass the 4TB RAID to my Windows 2008 R2 VM (And only allow it to access it). Basically Windows will then share this drive out via the network.... Do I just import it as another datastore and assign from there? I want to keep the RAID5 data from being "reliant" on ESXI... i.e So that I can remove the ESXI USB and boot from a Linux LiveCD and still see/access all the data on the raid5 array if needed.

^ If I create a "datastore" on my raid5 array, will the data then only be readable by ESXI?

I am a little confused, thanks for your help

 

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Yes.  You need to assign/create the datastore to the VM.  There may be a limitation on how much of that LUN can be passed.  Seems like I remember there being a limitation on the size unless you had a certain version of ESXi

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After doing a bit more research, I have found that RDM will allow me to "passthrough" a raw RAID5 Array to a VM (i.e write directly to the card array). The problem I face atm is getting ESXi5.1 to see more than 2TB of my 4TB array

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It seems that I am unable to add "Raw Device Mapping" - It's greyed out... Is this becuase the microserver doesn't support Direct Path I/O? Or is RDM unrelated to this?

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  • 2 weeks later...
  • 1 year later...

Hi Guys may i ask a quiestion regarding RDM proccess on HP Proliang G1610T Gen8 Microserver?

 

I am running latest HP Customized image 6.0.0 (May-2015) with older HPVSA driver due to speed issues.

 

I have 2x3TB WD-RED (RAID1) and 2x640GB (RAID1) and one SSD_240GB as an ESXi host datastore. Hypervisor is installed in MicroSD slot (8GB)

 

I managed to make both volumes (3TB) and (640GB) available on Virtual machines. I configure them as physical so i can run for example 3 or 4 VMs using same RAID1 volume.

 

My basic questions are:

 

1)Since both volumes (3TB) and (640GB) made RDM with relative commands (as physical) does RAID1 function (mirroring) continue to work as it should or this disrupted?

2)When i run 2-3VM's and making changes on RDM volumes (3TB) or (640GB) changes sometimes late to be replicated. Sometimes on Windows machines it needs to reboot or shutdown VM that make last change. Is that physical?

3)If i need to stop using RAID1 volumes as RDM i just delete VMDK file created or i should apply some commands? if yes please share with me a link if possible.

 

Thanks you all in adavnce for you replies.

 

Best Regards.

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After doing a bit more research, I have found that RDM will allow me to "passthrough" a raw RAID5 Array to a VM (i.e write directly to the card array). The problem I face atm is getting ESXi5.1 to see more than 2TB of my 4TB array

 

You cannot with RDM, You have to be at ESXI 5.5 with at least the first patch if using the HP image and then you can present volumes greater than 2TB by using VMFS instead of RDM.

 

EDIT: Ahh nice I see you found a workaround to present the raw volume then? I never thought of that but when I was doing it I specifically needed to find a way to house an enrormous share and still wanted to be able to have controll over the way it was provisioned, also it can be extended by adding more vmfs volumes anyway. Does it present a performance advantage? Only thing I can think of off the top of my head would be a case whereby you did something like Schoondoggy did recently sharing raw volumes via external cabling etc. with an N36L. Interesting neverhteless.

Edited by Helzy
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