According to this
http://gallery.technet.microsoft.com/office/Move-SharePoint-2013-242869e2
a possible solution seems to be to move the indexlocation by a powershell script:
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Name: Move-SPEnterpriseSearchIndex.ps1
Description: This script will move the SharePoint 2013 Search Index
Usage: Run the function with the 3 required Parameters
By: Ivan Josipovic, Softlanding.ca
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function Move-SPEnterpriseSearchIndex($SearchServiceName,$Server,$IndexLocation){
Add-PSSnapin Microsoft.SharePoint.PowerShell -ea 0;
#Gets the Search Service Application
$SSA = Get-SPServiceApplication -Name $SearchServiceName;
if (!$?){throw "Cant find a Search Service Application: `"$SearchServiceName`"";}
#Gets the Search Service Instance on the Specified Server
$Instance = Get-SPEnterpriseSearchServiceInstance -Identity $Server;
if (!$?){throw "Cant find a Search Service Instance on Server: `"$Server`"";}
#Gets the current Search Topology
$Current = Get-SPEnterpriseSearchTopology -SearchApplication $SSA -Active;
if (!$?){throw "There is no Active Topology, you can try removing the `"-Active`" from the line above in the script";}
#Creates a Copy of the current Search Topology
$Clone = New-SPEnterpriseSearchTopology -Clone -SearchApplication $SSA -SearchTopology $Current;
#Adds a new Index Component with the new Index Location
New-SPEnterpriseSearchIndexComponent -SearchTopology $Clone -IndexPartition 0 -SearchServiceInstance $Instance -RootDirectory $IndexLocation | Out-Null;
if (!$?){throw "Make sure that Index Location `"$IndexLocation`" exists on Server: `"$Server`"";}
#Sets our new Search Topology as Active
Set-SPEnterpriseSearchTopology -Identity $Clone;
#Removes the old Search Topology
Remove-SPEnterpriseSearchTopology -Identity $Current -Confirm:$false;
#Now we need to remove the extra Index Component
#Gets the Search Topology
$Current = Get-SPEnterpriseSearchTopology -SearchApplication $SSA -Active;
#Creates a copy of the current Search Topology
$Clone=New-SPEnterpriseSearchTopology -Clone -SearchApplication $SSA -SearchTopology $Current;
#Removes the old Index Component from the Search Topology
Get-SPEnterpriseSearchComponent -SearchTopology $Clone | ? {($_.GetType().Name -eq "IndexComponent") -and ($_.ServerName -eq $($Instance.Server.Address)) -and ($_.RootDirectory -ne $IndexLocation)} | Remove-SPEnterpriseSearchComponent -SearchTopology $Clone -Confirm:$false;
#Sets our new Search Topology as Active
Set-SPEnterpriseSearchTopology -Identity $Clone;
#Removes the old Search Topology
Remove-SPEnterpriseSearchTopology -Identity $Current -Confirm:$False;
Write-Host "The Index has been moved to $IndexLocation on $Server"
Write-Host "This will not remove the data from the old index location. You will have to do that manually :)"
}
Move-SPEnterpriseSearchIndex -SearchServiceName "Search Service Application" -Server "SP2013-WFE" -IndexLocation "C:\Index"