monaghant
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PowerEdge R620 PERC Setup for RAID 5

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Hi folks,

Just wondering could someone help me!

We’ve have just purchase a couple of new Dell R620 servers with 8 * 1 TB hard drives and I’d like to setup RAID 5 across all of the drives but when I set this up and go into Disk Management I can only see the 100GB drive I setup for the C drive for the OS etc. and I can create another drive at just under 2 Terabyte but I cannot create another volume for the remaining space which I can see as un-allocated and I wonder does anyone know now I can achieve RAID 5 across all of the 8 drives.

The servers OS is Windows Server 2012 R2 and I am aware of the issue with working with volumes above 2TB but am wondering does anyone know is there a way I can get  around this in the PERC configuration and Server 2012 R2 so all drives are accessible.

Sorry if I haven’t explained the question correctly but hopefully you know what I mean!

Thanks,

Tony

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6 Replies
Moderator
Moderator

RE: PowerEdge R620 PERC Setup for RAID 5

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unfortunately, no. this is because mbr initiallized drives can handle max 2TB. for larger volumes, youll have to use GPT (http://en.wikipedia.org/wiki/GUID_Partition_Table). unless you use UEFI instead of BIOS, windows wont allow a GPT boot drive.

there are no build in tools that can convert the drive loseless from MBR to GPT. so when you decide to setup again, either use UEFI as BIOS mode if your Motherboard supports that or try expose a smaller boot drive and a larger data drive as virtual drives from your raid controller

Regards,

Geoff P
Dell | Social Outreach Services - Enterprise


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monaghant
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RE: PowerEdge R620 PERC Setup for RAID 5

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Hi Geoff,

Thanks for your reply.

Ok I changed the setting in the BIOS utility to use UEFI from BIOS so what do I need to do know to allow me to use RAID 5 on all of the drives and how / where do I chose GPT instead of MBR?

Sorry, I'm new to all of the RAID stuff so any details on how to do this would be greatly appreciated.

Regards,

Tony

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Moderator
Moderator

RE: PowerEdge R620 PERC Setup for RAID 5

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Now that you have selected UEFI, you can create the GPT partitions as you install.  UEFI mode allows you to install to the larger partitions.  Create your OS partition, then you will be able to create the large data array. 

Regards,

Geoff P
Dell | Social Outreach Services - Enterprise


Download the Dell Quick Resource Locator app today to access PowerEdge support content on your mobile device!
(iOS, Android, Windows)

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monaghant
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RE: PowerEdge R620 PERC Setup for RAID 5

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Hi Geoff,

Thanks again for your reply and the very useful information!

OK so I switched from using BIOS to UEFI and booted up and began a fresh install. I created a 100GB C drive for the system OS and then created another volume with the remainder of the space which equated to nearly 6.5 TB. When the OS installed I notice there were a couple of extra volumes i.e. EFI system partition (100MB) and \ Recovery partition (300MB), is that normal enough? Also a lot of other space must be used in the background is there as we have 8 * 1 TB SAS drive but after the OS installed onto the 100GB drive and including the 2 other system partitions that only leave nearly 6.5 TB thus there is nearly 1TB missing. Would you have any idea how to reclaim that space or what is that being used for?

All seems fine and when I went into Disk Management and assigned a drive letter to the other drive with the remainder of the space that worked too. I now can see my C drive with 100GB and my E drive with 6.5TB space but if I check the properties of the E drive it still says file system is NTFS but I would have expected it to be GUID, so although I can see the large drive. What am I missing?!?!

I wonder where I see the GPT partition or is that hidden in the background as I was surprised to see the large drive having the NTFS file system. I think I understand the theory of what you are telling me here. Is the following statement correct –

“Basically if I switch from using the standard BIOS to use UEFI that then gives us the ability to work with larger volumes using the GPT partition instead of the MBR as it can only handle up to 2 Terabytes.”

Again, thanks for your advice and help with this!

Regards,

Tony

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theflash1932
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RE: PowerEdge R620 PERC Setup for RAID 5

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"I notice there were a couple of extra volumes i.e. EFI system partition (100MB) and \ Recovery partition (300MB), is that normal enough?"

Yes, that is normal for Windows to create the requisite partitions to manage the installation.

"Also a lot of other space must be used in the background is there as we have 8 * 1 TB SAS drive but after the OS installed onto the 100GB drive and including the 2 other system partitions that only leave nearly 6.5 TB thus there is nearly 1TB missing. Would you have any idea how to reclaim that space or what is that being used for?"

RAID stands for Redundant Array of Independent Disks, and that redundancy (ability to withstand a disk failure) comes at a cost.  That cost is disk space.  RAID 5 stripes the data together with "parity" data (used to calculate missing data when a disk fails) across all the disks in the array.  RAID 5 redundancy costs you one disk's worth of space.  So, if you have 8x1TB disks in a RAID 5, the total available space is 7TB (minus GB math).  If you have 3x1TB disks in a RAID 5, then the total available space is 2TB, etc.

"All seems fine and when I went into Disk Management and assigned a drive letter to the other drive with the remainder of the space that worked too. I now can see my C drive with 100GB and my E drive with 6.5TB space but if I check the properties of the E drive it still says file system is NTFS but I would have expected it to be GUID, so although I can see the large drive. What am I missing?!?!"

GUID is not a file system format ... GUID Partition Table (GPT) is the "disk" partitioning format.  The "disk" was converted to GPT (not MBR), allowing it to be mapped for partitions larger than 2TB, more than four primary partitions, large-disk bootable device, etc., but each of the partitions must still be formatted with a valid file system.  For Windows, that is FAT32 or NTFS.  NTFS is what you should be using for the Windows partition format.

" “Basically if I switch from using the standard BIOS to use UEFI that then gives us the ability to work with larger volumes using the GPT partition instead of the MBR as it can only handle up to 2 Terabytes.” "

Switching from BIOS to UEFI ONLY allows you to boot to a GPT "disk", and GPT is required for any "disk" over 2TB.  You could have left it in BIOS mode, then "sliced" the disks into separate RAID arrays.  Each RAID array is presented to the OS as a separate "disk", so you could have created a 100GB RAID 5 (which would have been MBR, presented to the OS as disk 0) for the OS, then created a RAID 5 with the remaining space (which would have been converted to GPT (and formatted as NTFS), presented to the OS as disk 1).

monaghant
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RE: PowerEdge R620 PERC Setup for RAID 5

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Hi theflash1932,

Thank you so much for your reply!  All of your answers above are very informative and both yours and Geoff's responses are very much appreciated.

Kind regards,

Tony 

 

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