Category Archives: Storage

Full or Thick Provisioned Volume on Compellent

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Introduction

There are pundits out there that claim that you cannot create a fully provisioned LUN on a Compellent SAN.  Now that what I call unsubstantiated rumors, better know as bull shit.

Sure the magic sauce of many modern storage array lies in thin provisioning. Let there be no mistake about that. But there are scenarios where you might want to leverage a fully provisioned volume. This is also know a s thick provisioned LUN. You can read about one such a scenario where they make perfect sense in this blog post Mind the UNMAP Impact On Performance In Certain Scenarios

Create a  Full or Thick Provisioned Volume on Compellent

First of all you create brand new volume in the Storage Center System Explorer. That’s a standard as it gets.

You then map this volume to a server

At that moment, before you even mount that volume on your server let alone do anything else such a bringing it on line or formatting it you’ll “Preallocate Storage” for that volume in Storage Center.

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You’ll get a warning as this is not a default action and you should only do so when the conditions of the IO warrant this.

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When you continue you’ll get some feedback. This can take quite some time depending on the size of the volume.

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When it’s done peek at the statistics of that full or this provisioned volume on the Compellent.This is what it looks like when you look at the statistics for that volume after is was done. So before we even formatted the volume on a server and wrote data to it. It’s using all the space on the SAN for the start.

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Due to data protection it’s even more. It’s clear form the image above that a 500GB disk in RAID 10 fully provisioned is using 1TB of space as its all still in RAID 10 (no tiering down has occurred yet). Raid 10 has an overhead factor 2. The volume is for a large part in Tier 2 because my Tier 1 is full, so writing spilled over into Tier 2.

Now compare this to a thinly provisioned volume that we just created and again we haven’t even touched it in any other way.

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Yup, until we actually write data to the volume it’s highly space efficient, there is absolutely no spaces use and we’ll see only a little when we mount, initialize the disk in Windows, create a simple volume and format it.image

This is completely in Tier 2 and my tier 1 is full. I accept donations of SANs and SSD’s for my lab it this bothers you Winking smile. When we write data to it you’ll see this rise and over time you’ll see it tier down and up as well.

DELL Compellent Storage Center 7.1 Certified for Windows Server 2016

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When it comes to selecting storage, especially when it comes to a “traditional” SAN, you all know that price performance wise I’ve been using the DELL Compellent series with great success for many years now. It’s a very capable solution that also has some other benefits when it comes to Windows Server and Hyper-V. It has one of the better hardware VSS providers, way better than average support for ODX  and UNMAP etc. but it’s also very good at delivering fast support for new versions of Windows Server. This has allowed us to move from Windows Server 2008 R2 to 2012 and from there to Windows Server 2012 R2 very fast.

In that regards I’m very happy to see that Storage Center 7.1 is already in the catalog as certified for Windows Server 2016.

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Customers that have up to date hardware and want to move fast to benefit from and leverage the new and improved capabilities in Windows Server 2016 Hyper-V, Clustering, Networking, …are ready to do so. Nice Smile.

Disk2VHD on a Generation 2 VM results in an unbootable VHDX

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Most people who have been in IT for a while will know the Windows  Sysinternals tools and most certainly the small but brilliant Disk2VHD tool we can use for Physical To Virtual (P2V) and Virtual to Virtual (V2V) conversions. It’s free, it’s good and it’s trustworthy as it’s made available by Microsoft.

For legacy systems, whether they are physical  with IDE/SATA/SAS controllers or virtual with an IDE generation 1 VMS thing normally go smooth.

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But sometimes you have hiccups. One of those is when you do a V2V of a generation 2 virtual machine using Disk2VHD. It’s a small issue, when you create a new generation 2 VM and point it to the OS vhdx it just won’t boot. That’s pretty annoying.

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Why do a V2V in such a case you might ask. Well, sometimes is the only or fasted way to get out of pickle with a ton of phantom, non-removable checkpoints you’ve gotten yourself into.

But back to the real subject, how to fix this. What we need to do is repair the boot partition. Well recreate it actually as when you look at it after the conversion you’ll notice is RAW. That’s no good. So let’s walk through how to fix a vdhx that your created from a source generation 2 Hyper-V vm via Disk2VHD.

First of all create a new generation 2 VM that we’ll use with our new VHDX we created using Disk2VHD. Don’t create a new vdhx but select to use an existing one and point it to the one we just created with Disk2VHD. Rename it if needed to something more suitable.

Don’t boot the VM but add a DVD and attach the Windows Server ISO of the version your vhdx contains to the DVD.

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Move the DVD to the top of the boot order I firmware.

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The VM will boot to the DVD when you hit a key.

Select your language and keyboard layoout when asked and the don’t install or upgrade the OS but boot

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Type diskpart and  list the disks. Select the disk we need (the OS disk, the only one here) and list the volumes. You can see that volume 3 off 99MB is RAW. That’s not supposed to be that way. So let’s fix this by creating boot loader directory structure, repair the boot record by creating the boot sector & copy the needed boot files into it.

Type:

select volume 3

assign drive letter L:

FORMAT FS=FAT32 LABEL=”BOOT”

That’s it we can now us that 99MB volume to make our disk bootable to windows again.  Type Exit to leave diskpart.

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So now we have a formatted boot partition we can create the need folder structure and fix the boot record and configure our UEFI bootloader

Switch to the L: volume

create efi\microsoft\boot folder structure for the bootloader as show below with the md command(make directory)

Type: bootrec /fixboot to create the bootrecord

Type: bcdboot C:\Windows  /l en-us /s l: /f ALL

This creates the BCD store & copies the boot files from the windows system directory

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Just click Continue to exit and continue to Windows Server 2012R2

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.. and voila, your new VM has now booted.

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Now it’s a matter of cleaning up the remnants of the original VMs hardware such as the NIC and maybe some other devices. The NIC is very important as it will have any static TCP/IP configuration you might want to assign tied to it which mean you can’t reuse it for your new VM. So, the 1st thing to do is uninstall the old network adapters from device managers, you’ll see them when you select “show hidden devices” in the view menu.

Good luck!

Fix virtual disk resizing issues with Gparted

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Introduction

I’ve discussed resizing virtual hard disks in Windows Hyper-V before. In Windows Server 212 R2 and the VHDX format even allows us to extend and shrink the virtual disks on line. For this they need to be attached to a vSCSI controller.

Extending virtual hard disks is something that rarely causes issues unless we don’t have enough disk space. Shrinking virtual disks has a few more potential issues to deal with which I discussed before. In that article I also showed ways to deal with those challenges.

One problem you can encounter is unused space that’s not located at the end of a virtual disk. This cannot be used to allow shrinking a virtual hard disk, the unused space has to be at the need of the disk. I mentioned using Gparted to fix this particular issue in a previous blog post You cannot shrink a VHDX file because you cannot shrink the volume on the virtual disk . Today we’ll show you how to fix virtual disk resizing issues with Gparted.

When doing P2V, V2V or even P2P the need to deal with legacy partition / volume layouts and other disk housekeeping tasks often arises. While the Windows inbox tools have gotten way better over the years we’re often left with lacking capabilities. Luckily there is Gparted the open source partition editor. Note that the use cases for Gparted go way beyond this particular use case.

A note on Gparted

With modern guest operating systems, you’ll want to use the latest x64 build of Gparted you can find. At the time of writing that’s 0.25.0-1 Make sure you grab the x64 version unless you’re still running older x86 edition of an operating system. I kind of hoping you’re not by now, but hey, I understand if you encounter them still.

The good news is that GParted works with both MBR and GPT disks, which is great. I don’t know about you but we’ve been using GPT by default everywhere we can for many years now to get rid of the 2TB limit. The bad news for some will be that, for now, it can only detect ReFS but cannot handle actions against it (yet?).

More information can be found at their Wiki and download are here

Fix virtual disk resizing issues with Gparted

A classic example of a disk with unused space that cannot be leveraged to shrink a virtual disk is the one where unused disk space is not at the end of the disk. Shrinking virtual disk with the inbox windows tools only works when that unused space is at the end of the disk and not in between partitions / volumes. Gparted can move a volume to deal with this. Another example is when system or other files are located at the end of an existing volume that has tons of free space but the files are blocking shrinking of the volume to create unused space that would allow the virtual disk to be shrunk. The latter can be dealt with by defragmenting the disk although you might need tools that can do off line defragmentation to move system files or you can also resize that volume with Gparted.

We’ll demonstrate this the use of Gparted with one such example, unused space in between partitions on a virtual disk. When that’s taken care of you can shrink the volume with Hyper-V manager.

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What I prefer to do is to create a temporary virtual machine to mount the ISO of Gparted and a copy the disk you want to work on. That leaves all the settings of the original virtual machine intact and working on a copy is save guard just in case things go wrong. When all went well you swap out the original disk on the production virtual machine for the one you edited. Naturally you can also do the work on the existing virtual machine. Which I what I’ll do here as a demo.

Step by Step

You can use a generation 2 virtual machine without issues as long as you make sure to disable secure boot. While on Windows Server 2016 you can select the correct boot template for secure boot with a Linux VM that won’t do the job here as the Gparted image doesn’t support secure boot.

Also note that a generation 2 virtual machine doesn’t have a virtual DVD drive by default so you’ll need to add one.

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Make sure the DVD drive is at the top of the boot order. That way the virtual machine will boot the GParted image from DVD automatically. If it doesn’t, some setting is wrong.

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Let the boot process continue and answer the request based on your needs or preference. I normally just go for the defaults (Keyboard, language, …)

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The GParted GUI will open for you automatically. You then need to select the correct disk to work on. This is one reason to use a dedicated workhorse virtual machine: less risk of selecting the wrong disk. Here is choose my 100GB data disk with the 2 volume and the unused space located between them.

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I select the partition I want to move and hit the resize button

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… and in the resize/move GUI is drag the partition at the end of the disk to the as much to the front as I can (green arrow)

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The GUI shows you layout you’ll get a result of your actions.

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Click on apply …

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You’ll get a warning you should heed and know what you are doing befor you continue. As it’s a data only disk we’re good.

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We hit OK and we’re warned that backups are important if thing go South. With virtual machines working on a copy of the virtual disk is also a good option. Better safe than sorry.

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We click on Apply and let Gparted work. I hope it’s clear that we do don’t shut down or power off the virtual machine during this time.

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Gparted is done. The move went successfully. Click on close.

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We now shut down the virtual machine.

Make sure you set re-enable secure boot if you were using it with a generation 2 virtual machine and check you have the correct template for your virtual machine.

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Remove the Gparted ISO image from the DVD. That will also remove it from the boot options where we set it as first in the boot order. Also don’t forget to remove the DVD, if you don’t want it there anymore.

Let’s boot our virtual machine and take a look at disk management:

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The picture in your virtual machine shows a volume layout in the guest on a virtual hard disk that we can shrink now using Hyper-V manager or PowerShell if we want to. Cool!

Conclusion

Sometimes the in box tools to deal with disks and volumes can’t handle specific situations but that doesn’t mean you’re stuck. We discussed how to fix virtual disk resizing issues with Gparted. This is a powerful open source tool that can be used for many disk and volume based operations on both physical and virtual disks. I’ve even used it to move my home workstation from SATA HHD to SATA SSD drives. If you’re ever in a situation where you need a very good partition / volume editor give it a go. I’ve been using it ages and it absolutely rocks!