Stuck when install simple W10 VM

[frankie666]

Hi, trying to create my 1st VM under W10... but it is stuck when copying files from install iso to vm. I have tried different setup of the VM and different ISO but always stuck at that stage (around 8% and 13%). What could be wrong in my setup ? Best and thx.

[bastl]

@frankie666 Make sure when you first create a VM to define the vdisk size in GB. If you don't enter a value a vdisk is created but only a couple MB. Also make sure not to use core0 for the VM. This core is always used by Unraid itself to do stuff in the background and can end in low performance for the VM.

 

With the following command you can show more infos about the created vdisk. Make sure the virtual size matches the value you defined and doesn't show a couple megabytes only.

qemu-img info /mnt/cache/VMs/Mint/vdisk1.qcow2

 

Adjust the path for the vdisk. In my example it's an qcow2 disk, but doesn't matter.

[frankie666]

23 minutes ago, bastl said:

@frankie666 Make sure when you first create a VM to define the vdisk size in GB. If you don't enter a value a vdisk is created but only a couple MB. Also make sure not to use core0 for the VM. This core is always used by Unraid itself to do stuff in the background and can end in low performance for the VM.

 

With the following command you can show more infos about the created vdisk. Make sure the virtual size matches the value you defined and doesn't show a couple megabytes only.

qemu-img info /mnt/cache/VMs/Mint/vdisk1.qcow2

 

Adjust the path for the vdisk. In my example it's an qcow2 disk, but doesn't matter.

 

Thanks for your reply. I have tried with core towards the end (as advised, ie cpu 3/7 in my case) but gives the same problem...

Size of the disk is 30Gb as requested.

 

[bastl]

@frankie666 Maybe try a fresh new Windows iso. In the last couple years I had 2 or 3 directly downloaded from MS which won't be able to install. Use the Media Creation Tool from Microsoft to download the current build. Maybe this helps.

 

Btw, how large is your cache drive and how much space is free?

[frankie666]

47 minutes ago, bastl said:

@frankie666 Maybe try a fresh new Windows iso. In the last couple years I had 2 or 3 directly downloaded from MS which won't be able to install. Use the Media Creation Tool from Microsoft to download the current build. Maybe this helps.

 

Btw, how large is your cache drive and how much space is free?

thanks @bastl, my cache drive is 99% full but as my domains share drive uses cache with "prefer" method I thouht it does not matter... Am I wrong? thx

[trurl]

22 minutes ago, frankie666 said:

my cache drive is 99% full

Why would you ever let it get that full?

 

22 minutes ago, frankie666 said:

domains share drive uses cache with "prefer"

Before files can overflow to the array, Unraid has to decide that it needs to choose another disk. It has no way to know in advance how large a file will become when it chooses a disk for it. Each User Share has a Minimum Free setting. If a disk has less than Minimum Free, Unraid will choose another disk. There is also a Minimum Free setting for Cache in Global Share Settings.

 

If a disk has more than Minimum Free, Unraid can choose it, and if the file won't fit the write will fail. You should set Minimum Free to larger than the largest file you expect to write.

 

Post diagnostics if you want more detailed advice on how to use cache.

[JonathanM]

49 minutes ago, frankie666 said:

my cache drive is 99% full

What is probably happening is that the vdisk file is being created on the cache drive, and when it tries to grow as you run the install it's filling the cache drive completely and failing. vdisks are created sparse, which means they only take up the space that's actually in use inside, but appear to the vm as having the full defined capacity available.

 

BTW, filling drives to 100% is a good way to corrupt the filesystem and lose all the data on the disk. Don't do that.

 

When defining a VM, best practice is to only size the virtual disk to partially use the free space available. While it's perfectly valid and sometimes useful to "overprovision", it can lead to nasty consequences if you don't manage the free space carefully. For example, I routinely provision more than 5 100GB VM's on my cache drive which only has 500GB total capacity, and generally stays about 1/2 full. Each VM thinks it has access to 100GB, when in reality it's only using 30 or so GB of space. If I start filling any of the VM's near capacity, I would crash them all if I run out of space, so I monitor the free space and deal with it before it gets anywhere close to filling the cache.

[frankie666]

ok, I am not used to use cache drive as you can understand... I will make some research on yt... in the meantime how to flush the cache drive ? i tried to invoke the mover but it seems not to do anything. thx

[JonathanM]

1 hour ago, frankie666 said:

in the meantime how to flush the cache drive ?

 

1 hour ago, trurl said:

Post diagnostics if you want more detailed advice on how to use cache.

 

[frankie666]

@jonathanm - Thanks for your reminder. I have done my homework on the cache behaviour and I was able to clear the cache drive and my vm is.... installing without any issue! Thanks to point up my mistake,

 

There is still one thing I don't understand... When you copy files to the nas, is the cache used ? if yes (my guess) when and can we choose to use it or not ? Hope the question is not too stupid. Thx again for your appreciated help.

[JonathanM]

On 1/5/2021 at 4:27 PM, frankie666 said:

When you copy files to the nas, is the cache used ?

Depends on which share you are copying to, and the specific cache settings for that share. Each share can be configured differently.

[trurl]

On 1/5/2021 at 10:16 AM, trurl said:

Post diagnostics if you want more detailed advice on how to use cache.