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PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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Ok,

I've got a problem.

We have a PE2950 laying around and want to use it as a simple backup device.  We purchased a bunch of 2TB drives, and then made a single RAID-5 ~9TB VD on the PERC 5/i the server uses.

When we attempt to install Windows 2008 R2 (Enterprise), we see that the first 2TB are available, and the last 7TB are unable to be accessed by the OS.

Likewise, if I attempt to install, partition, and format the array under the OS before installing, Windows automatically creates a bunch of paritions, and then automatically paritions out a 1.9TB section and a 7TB section.  [We install usinging a 100GB system parition, then carve the rest of the unused space later.

Why the heck can't we use anything on the PERC 5/i based array over 2TB?

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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I think you don't fully understand the difference between the partition table and the filesystem.

 

MBR (Master Boot Record) and GPT (GUID Partition Table) are the databases that keep track of where partitions start and finish. A computer with a BIOS cannot boot to a GPT disk. To boot to a GPT disk you have to have an EFI/UEFI. The MBR (database) option is capped at being able to address only the first 2TB (2048GB) of a (virtual/physical) disk.

 

Once the partition(s) is/are created, you then have to format it/them. This is where the filesystem comes in (e.g. NTFS or EXT4).

 

What you need to do is go into the PERC bios, delete your current config, then create a raid 5 on the PERC using all drives, however, change the size to just 100GB. Once this one is created, you install Windows on this.

At this point Windows only sees a 100GB disk (probably with a 100MB diagnostics partition and the rest as the C-drive).

Now you install Dell OpenManage Server Administrator with all options (some versions don't install the storage option by default for some odd reason). Now you use this to create a 2nd virtual disk on the remainder of the space.

This will show in Disk Management as a completely seperate disk (probably "Disk 1"). You online the disk and then initialize with with the GPT option. Now you can create a partition on there (max size).

Member since 2003

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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PS:   I did install Windows 2008 R2, and then ran the latest Server Update Disk on it.  So all of the firmware and drivers are up to date...

(Of course, I had to create a shotcut on the desktop, and then tell it to run in compatibility mode for "Server 2008 SP1," as Dell's SUU does support Windows 2008 R2...)

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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You're running into the limitations of having a bios.

 

To go over 2TB on a single (virtual) disk, you have to change to a different partitioning style; you have to change to GPT (default partitioning style is MBR). However, a computer that uses a bios, cannot boot the computer to such a disk.

You have a few options:

- create 2 virtual disks on the same set of physical drives; one for boot, the other for the rest of the disk space (downside is that you'll never be able to expand this raid set to include additional drives due to having 2 virtual disks on there)

- buy a Poweredge T710, go into the bios and change it to EFI. This will require you to install 2008 x64 or a later x64 OS, and the OS will automatically change the partitioning style to GPT, which will allow your bootdisk to be over 2TB (and fully use it).

Member since 2003

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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Ok,

So let me see if I understand this:

Basically, a Power Edge 2950 isn't going to support EFI?   ...and additionally, since I only have 5 disks in the PERC 5/i array, I the best I could hope to do is mirror the fist two disks (loosing 2TB in the process) and the RAID-5 the other 3 (loosing another 2TB)?

Interestingly, I just downloaded the latest version of Ubuntu (9.1) and installed it.  I created a 200MB /boot partition, a 8GB swap parition, and then a 9TB / parition.

Installed flawlessly.  So I gather the issue is the OS?  ...and is there ANY way to get around this?

If I were to install the OS on an iSCSI target, and then create a GPT disk on the PERC 5/i's RAID-5 VD, would that work?

PS Why buy another Dell server if they can't keep their slightly older, but recent, servers up-to-date?  That's asking to pay for it twiece.  Not to mention that Dell has been aware of high capacity storage options [e.g. hard disks] for a long time, so it's much more likely that they are not interested in helping people avoid purchasing an EqualLogic SAN, etc.  Based on what your saying, it's a simple matter of writing an EFI BIOS extension, and updating the firmware on one of their most widely used PERC adapters. I understand that many folks might not go down this path, or even try it... but by the same token, why wouldn't you try it?

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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The first Dell servers to offer UEFI are the 11th generation servers (not 100% sure if the lower end ones do, but the 610 and 710 servers definitely have the option in the bios).

 

It surprises me that Ubuntu was able to use the whole disk, as the MBR 'database' cannot address the space after the 2TB point on a disk, so it shouldn't be able to put a partition there. I wonder if Ubuntu maybe doesn't realize the size and if you were to try and load up that disk space (after filling up the first 2TB), if the data would still be usable.

 

You can create the raid 5 with a 50GB first virtual disk for boot-only (install Windows there), and then a 2nd virtual disk on the raid 5 that makes up the rest of the disk space. This just means that you'd never be able to grow the raid 5 to 6 (or more) disks (may need to transplant the drives to a different system to have the slots for that many drives obviously).

Member since 2003

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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We didi try that... 100GB system partition, and then make the rest a GPT partition, but it doesn't work using the Windows 2008 R2 Install DVD.

What you get is:

100MB [Windows "special" partition]

100GB System Partition

1.9TB Unallocated Space

7TB Unallocated Space

...or did you mean the idea of using a iSCSI target, and then GPTing the compelte local RAID array?

 

PS Ubuntu used EXT4 as the file system type, and I'm fairly sure it used GPT for everything.

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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I think you don't fully understand the difference between the partition table and the filesystem.

 

MBR (Master Boot Record) and GPT (GUID Partition Table) are the databases that keep track of where partitions start and finish. A computer with a BIOS cannot boot to a GPT disk. To boot to a GPT disk you have to have an EFI/UEFI. The MBR (database) option is capped at being able to address only the first 2TB (2048GB) of a (virtual/physical) disk.

 

Once the partition(s) is/are created, you then have to format it/them. This is where the filesystem comes in (e.g. NTFS or EXT4).

 

What you need to do is go into the PERC bios, delete your current config, then create a raid 5 on the PERC using all drives, however, change the size to just 100GB. Once this one is created, you install Windows on this.

At this point Windows only sees a 100GB disk (probably with a 100MB diagnostics partition and the rest as the C-drive).

Now you install Dell OpenManage Server Administrator with all options (some versions don't install the storage option by default for some odd reason). Now you use this to create a 2nd virtual disk on the remainder of the space.

This will show in Disk Management as a completely seperate disk (probably "Disk 1"). You online the disk and then initialize with with the GPT option. Now you can create a partition on there (max size).

Member since 2003

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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Yep.  That did it.

Worked like a champ.

Duh!

Thank you!

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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Hi all I found myself in the same predicament. I had backed up my work and was going to run a BMR after I re-configed the RAID. I booted up and I had the wrong network driver so I couldn't restore. Not a big deal I'd just have to build a new restore CD but I rebooted the box and low and behold the server came back up after blowing away the RAID config! When I recreated the virtual disk I did not initialze the drives. Is this typical behavior or am I just incredibly lucky?

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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as long as  you dont initialize the drives, the container is still there. As an example, you could have system A with a raid 5 config  up and running, take the drives out, insert into (a like)system B with no raid config, and the controller would see the config on the drives, load that and run properly.

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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What about new 3Tb drives on 2950 with the raid/bios perc5?  Will it work?

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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No, 3TB drives are not an option on a 2950.  The only Dell controller that can handle >2TB drives is the H700, which is not supported on the 2950.  2TB is a common limitation that is currently being addressed, but the need to is a fairly recent one, so it will take some time before it is "mainstream".

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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For what it's worth, I was able to take a 2950/Perc5/i integrated with 6x3.5" SAS backplane and install 6 2TB SATA drives, build a ~11TB RAID5 virtual disk in the controller (boy did it take a while to initialize), and install Openfiler 2.3x64 on the VD.  I used about 100GB of the VD as boot/root/swap in three partitions, and set up the remaining ~11TB as an iscsi target in Openfiler which I could mount and partition in 2008 R2 from another machine (GPT partition only) with Windows iscsi initiator.  I'm using that for backup with imaging/continuous BDR.

Since the controller sees the ~11TB VD I imagine you could just as easily load 2008 R2 in 100GB MBR and use the rest GPT.  Since 6x2TB maxes the current capacity, no need to worry about expanding the RAID set later.  🙂

I can also confirm 3TB drives do not work in this configuration with the latest firmware and BIOS, and they register to the Perc as 2TB drives.  Hopefully Dell will eventually provide some firmware updates for this, I have a bunch of 2950's I'd rather not replace now either and this limitation really should be lifted for the 2950 generation.

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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Glad to hear you got things working ok.  The 2TB limit on the PERC 6 is not a limitation imposed by Dell because of firmware restrictions they've put in place, but a limitation of the controller hardware itself.  It is not possible for a PERC 6 to see >2TB drives.  I've heard someone successfully installed and is using an H700 controller in a 2950 though.  And just for the sake of pointing it out, the 2950 is not UEFI-capable (BIOS updates also cannot "fix" this limitation) either.

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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That is great news to hear. I have recently acquired a 2950 for the same purpose and I have been looking for the right 2TB drive. The Seagate ST2000DM001 and the Western Digital WDBAAZ0020HNC-NRSN look good but I wasnt sure about how much of a performance gain I would see from a buffer of 32mb to 64mb. What drives did you end up with and are you happy with the performance?

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Re: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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I recently tried the WD RE4 2 TB drives as they are designated for server RAID service; seem to be fine.  I also have the same issue with the 2 TB limit and am trying the 100 GB initial RAID5 and server manager to create the remaining space.  I may just create a series of 2TB partitions to keep it simple.

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RE: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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Trying to get Windows Server 2008 to work with 10TB on a PE 2950, with a raid 5 config.

This worked like in the most brilliant of fashions. I did exactly what DEV MGR suggested and bang success. Many thanks for this post and triple thanks to DEV MGR. I hope this will help some one else.

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RE: PERC 5/i / PE2950 / RAID-5 w 2TB drives / Windows 2008 Issues

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Thanks your solution run perfectly for me!!!

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