Handling “There is not enough space on the disk” exception with ASP based service in Windows Azure

If you have deployed an
ASP.NET based service on Windows Azure and while uploading a large file using
ASP.NET upload functionality or HTTP upload, you might receive the following
error:

Error: There is not enough space on the
disk

This error could appear in several way however a
few are described as below:

Case [1]: While accessing your ASP content you
might hit the following error just randomly:

Case [2]: You might get this error when you will
use ASP upload function to upload a file which is larger than 100MB or in some
case under 100 MB.

There is not enough space on the
disk.

Description: An unhandled exception occurred
during the execution of the current web request. Please review the stack trace
for more information about the error and where it originated in the
code.

Exception Details: System.IO.IOException: There is
not enough space on the disk.

Source Error:

An unhandled exception was generated during the
execution of the current web request. Information regarding the origin and
location of the exception can be identified using the exception stack trace
below.

Stack Trace:

[IOException: There is not enough space on the
disk.]

System.IO.__Error.WinIOError(Int32 errorCode,
String maybeFullPath) +10546789

System.IO.FileStream.WriteCore(Byte[] buffer,
Int32 offset, Int32 count) +10351324

System.Web.TempFile.AddBytes(Byte[] data, Int32
offset, Int32 length) +26

System.Web.HttpRawUploadedContent.AddBytes(Byte[] data, Int32 offset, Int32
length) +327

System.Web.HttpRequest.GetEntireRawContent()
+515

System.Web.HttpRequest.GetMultipartContent()
+72

System.Web.HttpRequest.FillInFormCollection()
+248

System.Web.HttpRequest.get_Form()
+79

System.Web.HttpRequest.get_HasForm()
+73

System.Web.UI.Page.GetCollectionBasedOnMethod(Boolean dontReturnNull)
+54

System.Web.UI.Page.DeterminePostBackMode()
+90

System.Web.UI.Page.ProcessRequestMain(Boolean
includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
+268

Case [3]: While you are uploading a large file to
Azure blob storage from your ASP page you might get the same
error:

FileUploaderHandler: There is not enough space on
the disk.

at System.IO.__Error.WinIOError(Int32 errorCode,
String maybeFullPath)

at System.IO.FileStream.WriteCore(Byte[] buffer,
Int32 offset, Int32 count)

at
System.Web.HttpRawUploadedContent.TempFile.AddBytes(Byte[] data, Int32 offset,
Int32 length)

at
System.Web.HttpRawUploadedContent.AddBytes(Byte[] data, Int32 offset, Int32
length)

at
System.Web.HttpRequest.GetEntireRawContent()

at
System.Web.HttpRequest.get_InputStream()

at
WebRole1.FileUploadHandler.ProcessRequest(HttpContext
context)

In all the above cases as
well as the others who receive similar exception the problem is same. The
problem is that the ASP use a temp directory size which includes compiled binary
as well as used as the temp folder while uploaded. At any given time, depend on
available space in the temp directory, you will face a file upload limitation
with files size 100MB or higher and in some case files under 100MB as (when
there are lots and lots of compiled ASP content. The following factors with TEMP
folder are causing this issue;

1. The maximum size of ASP temp folder is 100
   MB
2. The size of ASP temp folder cannot be
   changed
3. The ASP TEMP folder location cannot be
   changed
4. IIS main configuration cannot be changed for
   several other reasons so even when you will use:

<httpRuntime
maxRequestLength="<Some_High_Value>" executionTimeout="3600"
/>

Or

<requestLimits
maxAllowedContentLength="<Some_High_Value>" />

So even when you are using webserver settings to
extend the upload size, still the default temp size cannot be changed. As the
ASP temp folder location and size is fixed for 100MB so user cannot upload more
than 100MB files or if the temp folder is filled with ASP binaries then page
accessibility could be another issue.

Also in case of someone accessing Azure Storage
from ASP (Case #3), the same problem also cause this error. And the reason for
this error is that when you will use Azure Storage API in ASP i.e.
(UploadFromStream() function within ASP) the file will be uploaded using HTTP
Post method from your machine to Azure Service first and then transferred from
ASP temp folder to Azure Storage. This will hit the same problem as I described
earlier. So in summary, UploadFromStream() doesn’t use the temp folder, but
ASP.NET handling an incoming HTTP post does which will cause the
problem.

Solution:

If you are using Cloud SDK 1.2 you have the
following options to solve this problem:

1. Use 3rd party ASP upload component which
does not use ASP.NET temp folder

2. User Silverlight based HTTP upload which
does not use ASP TEMP folder

3. Create your own ASP.NET upload component
which does not use ASP.NET temp folder

4. You can also solve this problem by running
IIS inside the worker role which is also defined as “Hostable Web Core (HWC)”.
This is a little complex solution however if you really have no way to live with
the problem and need solution, HWC is the best way to go. There are lots of
companies using HWC solution so it is a good solution if needed. You should be
able to take smarx’s blog post (link below) to start HWC
sample:

https://blog.smarx.com/posts/build-your-own-web-role-running-hosted-web-core-in-windows-azure

I have also created the following tutorial to use
the sample at dev fabric and on cloud which will be very helpful to you
also

https://hwcsample.cloudapp.net/

With Cloud SDK 1.3, which is scheduled to release
by end of this year (2010), you can use the IIS role in the service then your
web.config setting will work to change the ASP temp folder size or location. As
of now SDK 1.3 is not publically available so if you follow this solution you
will have to wait its release.