Use hardware VSS writers in DPM 2012 R2:

I was trying to leverage our SAN hardware’s snapshot capabilities for backup and restore purposes. I noticed that DPM is able to use hardware VSS writers instead of using the regular VSS software provider. The advantage is that snapping is done by the hardware….meaning it is much faster!

Here is how I did it for our 3PAR 7400 SAN and our LeftHand P4000 SAN. The backup software I am using is SC DPM 2012 R2

Steps to be taken on all backup servers, all Hyper-V nodes in the HV cluster and all Hyper- Standalone nodes:


1. Install DOT NET 3 from “Add Roles and features” in Server Manager

2. Install CLI tools for 3PAR.

3. Install “Hardware VSS Provider” for 3PAR

4. Install LeftHand Application Aware Snapshot Manager (their VSS provider)

5. Make sure both VSS providers authenticates properly with both SANs

6. On an elevated cmd prompt run

vssadmin list providers

You should see the 3PAR Hardware VSS Provider listed (earlier it was not)


Steps to be taken on the backup server running DPM:


Follow instructions listed here:

Note: On my DPM 2012 R2, we only had this file DatasourceGroupsSample.xml. I deleted it.

Upon running a backup again, I see snapshots getting created in both the SANs. Yahoo!

There is always something…

There is still one problem…the snapshots (even though they are on the SAN) get transferred over the regular TCP/IP network to the backup server’s local disk array. I want them to be transferred over Fiber Channel or iSCSI, depending upon the SAN’s connectivity. At this point, I am searching for an answer to this last piece of the puzzle.

The documentation of both hardware VSS writers I implemented say that it is do-able….but DPM is not doing it, right now. If I find the solution, I’ll post it here.

Thin provisioning savings in a 3PAR SAN

I recently implemented a 3PAR SAN. After migrating 10-15 VMs onto it, I looked at the disk utilization. I was happy to see how good the thin provisioning in the 3PAR SAN’s operating system was working.


  • Total space the Hyper-V servers “think” they have = 1600 GB
  • Total space the Hyper-V servers “think” they have used = 596 GB
  • Actual space the SAN has reserved for these LUNs =  403 GB

So that counts as a savings of around 193GB worth of real disk space (32%). Sweet, eh?)

Full details below.

Continue reading “Thin provisioning savings in a 3PAR SAN”

Presenting LUNs to Hyper-V 2012

Here are my notes on presenting a LUN from a 3PAR 7400 SAN to a Hyper-V 2012 server running no GUI. The SAN is connected to the server via Fiber. There is a FC switch in between which has been properly configure, zoned, etc. Multiple paths to the same LUNs are configured for redundancy and speed so we need MPIO.


1. Install MPIO feature and reboot the Hyper-V server

Note that I did not run the mpiocpl GUI or the mpclaim command as I described here earlier. You may have to do that.

2. From  inside the SAN management console, present a LUN to the Hyper-V server.

Note: while creating the volume/LUN make sure to check the size against the “Chunklet Calc” worksheet inside this spreadsheet – “3PAR Design Spreadsheet v2” so that  no chunklets are stranded. For example, it is better to have a 504 GB LUN than a 500 GB LUN. A 10 GB LUN wastes 6 GB space! A 16 GB LUN wastes nothing. So you  have to play around with the numbers in the spreadsheet.

3. At this point you have two options – use GUI disk management tool from a remote client machine running Windows 8 OR on Hyper-V server itself run these commands:


DISKPART>list disk (You may see your disk listed but if not run a rescan command)


DISKPART>list disk (Now you should see your new disk listed but it probably is offline)

DISKPART>list volume (this shows all your current volumes and their drive letters)

DISKPART>Select disk 1

DISKPART>online disk

DISKPART>detail disk (this will give you detailed info)

DISKPART>attributes disk clear readonly


DISKPART>convert mbr

DISKPART>create partition primary

DISKPART>select part 1

DISKPART>format fs=ntfs label=SANtest quick

DISKPART>assign letter E

DISKPART>list volume (you should see the new volume  now)


Full diskpart syntax can be seen here

Credits and more information here