topic Re: How do I provide BlockRanges to Start-NaClone in Microsoft Virtualization Discussions

How do I provide BlockRanges to Start-NaClone

ktim — Thu, 05 Jun 2025 05:59:10 GMT

I'm trying to do a sub-file clone using the toolkit. Start-NaClone has a [-BlockRanges <BlockRange[]>] parameter.

Each block range is an instance of type DataONTAP.Types.Clone.BlockRange, but I can't work out how to populate a BlockRange object, and can't find any examples or documentation around this.

Any ideas?

-Tim

Re: How do I provide BlockRanges to Start-NaClone

vinith — Fri, 05 Jul 2013 06:41:02 GMT

Check out the help for this cmdlet.

Get-Help Start-NaClone -Examples

PS C:\Windows\system32> Get-Help Start-NaClone -Examples

NAME

Start-NaClone

SYNOPSIS

Starts a file/LUN or sub-file/sub-LUN clone operation.

-------------- Example 1 --------------

C:\PS>Start-NaClone /vol/vol2/lun1 /vol/vol2/lun1clone

Create a clone 'lun1clone' of LUN 'lun1'.

SourceFile : /vol/vol2/lun1

DestinationFile : /vol/vol2/lun1clone

CloneState : running

TotalBytes : 21476192256

PercentDone : 0

BytesCopied : 0

CloneType : lun

CloneId : 12

Error :

Reason :

-------------- Example 2 --------------

C:\PS>Get-NaLun /vol/vol2/lun1 | Start-NaClone

Clone LUN 'lun1' and accept the default destination name 'lun1Clone'.

Re: How do I provide BlockRanges to Start-NaClone

ktim — Fri, 05 Jul 2013 06:43:50 GMT

Hi Vinith,

Been there... no information on how to construct BlockRanges...

Regards,

Tim

Re: How do I provide BlockRanges to Start-NaClone

beam — Mon, 08 Jul 2013 17:00:08 GMT

Hi Tim,

The BlockRange object is a block range descriptor containing three key fields: SourceBlockNumber, DestinationBlockNumber, and BlockCount. For LUNs, these block ranges are 512-byte LBA ranges, and for WAFL files they are 4k blocks.

You can create a BlockRange object using the New-Object cmdlet, for example:

$blockRange = New-Object DataONTAP.Types.Clone.BlockRange

$blockRange.SourceBlockNumber = 0

$blockRange.DestinationBlockNumber = 1024

$blockRange.BlockCount = 4096

Calculating the block ranges is the tricky part. For WAFL files it is fairly straightforward as long as you remember there are 4096 bytes in a WAFL block. If you are trying to sub-file clone a file on a LUN, it is significantly more complicated (and risky). You must find the block ranges the file occupies on the LUN, then calculate which block ranges fall in the part of the file you want to clone. Copy-NaHostFile handles this for you, but does not do sub-file cloning. Getting the source and destination block numbers wrong could very easily corrupt the LUN.

-Steven

Re: How do I provide BlockRanges to Start-NaClone

ktim — Tue, 09 Jul 2013 00:43:12 GMT

Fantastic. Thanks Steven!

Calculating the block ranges is no problem... just want to have as few calls to Invoke-N?SystemApi as possible...