Storage Spaces: Virtual Disk taken offline during file copy, marked as "This disk is offline because it is out of capacity", but plenty of free space

D

David Trounce

Server 2012 RC. I'm using Storage Spaces, with two virtual disks across 23 underlying physical disks.

* First virtual disk is fixed provisioning, parity across 23 physical disks: 10,024GB capacity
* Second virtual disk is fixed provisioning, parity across the remaining space on 6 of the same physical disks: 652GB capacity

These have been configured as dynamic disks, with an NTFS volume spanned across the two (larger virtual disk first). Total volume size 10,676GB. For more details of the hardware, and why the configuration is like this, see: Storage Spaces - functionality missing in beta, but planned for RTM?

I'm copying several TB from a network share to this volume. It is very slow at ~12MB/sec, but works. However, three times so far, several hours in to the file copy and with plenty of free space remaining, the 10,024GB virtual disk is suddenly taken offline. This obviously then fails the spanned volume and stops the file copy.

The second time, I took screenshots, below. The disk (Disk27) is marked offline due to "This disk is offline because it is out of capacity". And the disk in the spanned volume is marked as missing (which is what you would expect when one of its member disks is offline).

117624.png


I can then mark the disk (Disk27) back online again, and this restores the spanned volume. I can then re-start the file copy from where it failed. There doesn't appear to be any data loss, but it does cause an outage that requires manual attention. As you can see, there is plenty of space left on the spanned volume.

117628.png


Each time this has happened, there are a few event 150 errors in the System event log: "Disk 27 has reached a logical block provisioning permanent resource exhaustion condition.". Source: Disk.

- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
<Provider Name="disk" />
<EventID Qualifiers="49156">150</EventID>
<Level>2</Level>
<Task>0</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2012-06-07T11:24:53.572101500Z" />
<EventRecordID>14476</EventRecordID>
<Channel>System</Channel>
<Computer>Trounce-Server2.trounce.corp</Computer>
<Security />
</System>
- <EventData>
<Data>\Device\Harddisk27\DR27</Data>
<Data>27</Data>
<Binary>000000000200300000000000960004C0000000000000000000000000000000000000000000000000</Binary>
</EventData>
</Event>

This error seems to be related to thin provisioning of disks. I found this: http://msdn.microsoft.com/en-us/library/windows/desktop/hh848068(v=vs.85).aspx. But both these Virtual Disks are configured as Fixed, not Thin provisioning, so it shouldn't apply.


My thoughts: the virtual disk should not spuriously go offline during a file copy, even if it was out of space. And in any case, there is plenty of free space remaining. Also, I don't understand the reason for why it is marked as offline ("This disk is offline because it is out of capacity"). Why would a disk go offline because it was out of thin capacity, rather than just returning an "out of disk space" error while keeping it online.

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