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RAID on the N54L without an external card


frankplummer
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Following on from my other post, I'm quite keen to get peoples thoughts on using the built-in RAID on the N54L/Gen7 MicroServers to get a RAID1 mirrored setup working in a hypervisor environment.

 

My aim is to use a N54L for two purposes; as a NAS with two 2TB drives in RAID1 and as a hypervisor to run virtual machines with a datastore on a seperate (non-RAID) drive.

 

I understand that ESXi 5 and XenServer do not play well with the built-in RAID on the N54L. Is there any workaround for this if I wanted to use either of these operating systems? Could I pass-through the two 2TB drives and have a guest running FreeNAS or Openfiler with software RAID1 to provide NAS functionality?

 

Does Windows Server 2008R2/2012 support the N54L built-in RAID? I have a license available for both and have no problem using Hyper-V if I can achieve the NAS/hypervisor functionality detailed above, but I have used ESXi for years and would prefer to stick to that if I can.

 

I'm not in a financial position to obtain a RAID card so my options I realise are limited. I haven't found any solid information on the web as to what operating systems do support the built-in RAID and I'm keen to learn what success you guys have had with it.

Edited by frankplummer
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I can see that your asking specifically about using the hardware RAID with a Hypervisor like ESXi or XenServer but you also mentioned the option of using Software Raid.

 

My current system is running on an N40L using VMWare ESXi.  I run 3 virutal machines for differing purposes however, one of the VMs is running WHS2011.

 

The WHS2011 VM has the 2 x 2TB and 1 x 1TB hardisks mapped as Raw Device Mapping (RDM) direclty to the WHS2011 VM.

 

Inside WHS2011 I am using Windows software to RAID 1 the 2 x 2TB drives and the 1 x 1TB is used as non-critical storage.

 

The Hypervisor runs on USB stick with the OS Store running on a seperate 120GB SSD.

 

The whole solution seems to work and whilst its not hardware "pass-through" in the true sense, using RDM does give me the added benefit that all the data stored on the RAID 1 drives are in native NTFS format which I could easily remove from the server and plug into another system for disaster recovery if it all went wrong.

 

In terms of performance, I have not hit any bottlenecks with this configuration.  The drives manage a transfer rate of about 80MBPS through to the network interface.

 

This is probably the only real solution you have.  I looked for any alternative options and came up blank but I'm pretty happy with how this has worked out.

 

The only minor niggle that remains is that if I want to shut down the Hypervisor, I need to manually shut down the WHS2011 VM first otherwise when it restarts, the RAID 1 array starts to resync upon reboot.  

 

This seems to be related to VMware tools not doing a clean shutdown within the VM before powering off so the Windows detects the improper shutdown and resyncs the array.

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I can see that your asking specifically about using the hardware RAID with a Hypervisor like ESXi or XenServer but you also mentioned the option of using Software Raid.

 

My current system is running on an N40L using VMWare ESXi.  I run 3 virutal machines for differing purposes however, one of the VMs is running WHS2011.

 

The WHS2011 VM has the 2 x 2TB and 1 x 1TB hardisks mapped as Raw Device Mapping (RDM) direclty to the WHS2011 VM.

 

Inside WHS2011 I am using Windows software to RAID 1 the 2 x 2TB drives and the 1 x 1TB is used as non-critical storage.

 

The Hypervisor runs on USB stick with the OS Store running on a seperate 120GB SSD.

 

The whole solution seems to work and whilst its not hardware "pass-through" in the true sense, using RDM does give me the added benefit that all the data stored on the RAID 1 drives are in native NTFS format which I could easily remove from the server and plug into another system for disaster recovery if it all went wrong.

 

In terms of performance, I have not hit any bottlenecks with this configuration.  The drives manage a transfer rate of about 80MBPS through to the network interface.

 

This is probably the only real solution you have.  I looked for any alternative options and came up blank but I'm pretty happy with how this has worked out.

 

The only minor niggle that remains is that if I want to shut down the Hypervisor, I need to manually shut down the WHS2011 VM first otherwise when it restarts, the RAID 1 array starts to resync upon reboot.  

 

This seems to be related to VMware tools not doing a clean shutdown within the VM before powering off so the Windows detects the improper shutdown and resyncs the array.

Thanks for the detailed reply - you've given me exactly what I needed. I thought something along these lines was my only route to go down and it sounds perfect. Very happy to have a WHS/2008R2 guest running as the NAS managing the RAID1 array and have ESXi managing datastores elsewhere. Sounds like an ideal solution! Can I ask how you use the SSD in your MicroServer? Do you have the modded BIOS or does the SSD work just fine without any performance modifications?

Edited by frankplummer
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I only recently installed the SSD to use as the Operating System Datastore.

 

Previously the VM's were stored on a 3.5 inch HDD located in the first bay of the HDD rack but the HDD was limiting the performance of the VM's and I was concerned that over time the HDD might become a point of failure due to non-stop operation 24/7. 

 

I left the original HDD in place and installed the SSD in the optical drive bay in a Thermaltake Duo 5 Dock.  The dock was not completely necessary but I did like the idea of being able to drop a 3.5 inch HDD into the dock for back up purposes (I'll come back to this).

 

I didn't test the SSD on the ODD port before installing the modded bios so, I'm afraid I can't give you any feedback on whether the performance improvements warranted the bios change.  If you feel uncomfortable installing the mod bios Im sure the performance at SATA1 speed will still be more than adequate.   Alternatively, install the SSD in a HDD bay.  I've see postings elsewhere where a guy plugged the SSD directly into the backplane without an adaptor.  The SSD's are so light that the plug connection alone is enough to hold the drive in place.

 

So in short, the SSD holds only the VM's.  The old OS_Datastore HDD is there as a backup to the SSD in case it failed.  I can simply start up another VM off the mechanical HDD if the SSD fails and pick up where I left off.

 

I mentioned the backups earlier.  One problem with any VM on ESXi is that if you plan to backup your data with a USB external drive or similar, it is painfully slow.  The performance of USB inside a VM is woeful.

 

A better option is to use the Esata port and map that into your WHS VM.  I haven't got quite that far yet.  I'm waiting for my SATA to ESATA cable to turn up in the mail which will allow me to use the 3.5 bay on the HDD dock connected via the external ESata port.  Of course to do this, you absolutely need the bios mod installed.

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Brilliant - thanks once again for your input. You have the setup I was more or less originally hoping to achieve with my new N54L. It's reassuring to know someone has been through the motions themselves so I can extract what I need to from there experience. I'll be using a 130GB SSD for a VM datastore with the original 250GB spare, most likely as a backup like you use yours now, and the higher capacity drives mapped as RDM to a Windows Server 2008R2/2012 guest to run the RAID array.

 

When I get home on Monday, I'll surely try all this out!

 

Many thanks!

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