Make physical disks available to guest (Debian) on ESXi 5

[ViiJay]

Hello community,

first of all I am not sure if this is the correct approach for my problem so let me quickly sum up what I want to do.

For my home use I want to setup a linux server (besides others) as guest which has to has access to several physical disks. Due to a small pocket I used a single Debian installation on one server which covered all my needs. Now I want to split this into different systems, virtualized. One of them is my storage where I put all my files. For now I was using a software raid 5 (yes I feel so poor even writing this) on a debian and was wondering if there is any possibility to achieve this within ESXi 5?

tl;dr:

Can I give a guest system physical access to several locally connected S-ATA hdd drives (connected via a Intel / LSI S-ATA controller) to make a software raid on the guest system?

Maybe a virtualization is the wrong way and I should just put every task back on one server again without virtualization.

Thanks in advance,

Yours ViiJay.

[weinstein5]

Welceom to the Communtiy - yes you can througfh the use of a feature called Raw Device Mapping (RDM) - basically creating a proxy virtual disk that will redirct the reads/writes to the Raw Disk - the potential is working with local storage - the esxi host will need to see all the disks

[ViiJay]

Hello weinstein5,

first of all thanks for you quick reply. This could do the trick and I will give it a try soon. I found a how-to to create an RDM from the shell. I should be able to do that.

One last question regarding my scenario. If I have let's say like 4 drives defined as a RDM and my Debian guest system will be able to access those drives and create a software-raid (RAID 5), what would happen if one drive would fail? I know this is far fetched but essentially this is what this whole thing is about. I don't want to loose my data if one drives decides to jump the cliff. And yes, of course I should do backups...

Thanks again for your help and advice.

Regards,

VJ

[Virtualinfra]

Raid volume(logical volume) is configured as RDM on the virtual machine.. incase 1 drive fails still the data is available to the virtual machine..

Raid redudancy is applicable for the datastore space..

[mcowger]

The same thing as if it were a phsyical system. 

If you had configured RAID0, you are screwed.  RAID5, you'd be fine.  RAID 10, you'd be fine, etc.

[brmovem]

Hello ViiJay!

Could you please post here a link to that manual about RDM?

It'd be useful for me too.

Thank you.

[ViiJay]

First thank you all for the input and knowledge you guys are sharing. This helps ... A. LOT.

@Virtualinfra and mcowger:

Thanks for the advice. I am going to build a RAID-5 so 1 hard drive failure should be fine. Unfortunately hard drive prices are through the roof why I am going to wait a little longer to stock up my disk space.

@brmovem

Actually I couldn't find that one webpage I was looking for and was mad at me for not bookmarking it. But ... I probably found something even easier. I got the problem that the RDM option when adding a hard disk to a VM was greyed out. So I found this VMWare KB article which gave me the solution. Just take your vSphere Client and go to Configuration -> Advanced Settings -> Rdm Filter and uncheck the "RdmFilter.HbaIsShared" checkbox. After deactivating that checkbox the option at least is available. I haven't tried though if it is working but this way is much easier than hacking it into a console.

Hope this could be of help.

Regards,

VJ