new EVA announcement...

[Tom O'Toole]

Does anyone know if the new LUN size-reduction feature is for the new EVA models only, or will it be available in all models given new enough firmware? My impression is the latter, but can't really tell. The only immediately apparent differences to me in the new series of EVAs are the switched disk enclosures and a 24% performance increase (not saying that's bad)...

Anyone know if there are any plans for LUN size reduction on non-MS systems (in particular Openvms). To be able to (manually, not automatically) 'give back' allocated capacity seems like a useful feature.

[Rob Leadbeater]

Hi Tom,

The LUN shrinking feature would appear to be part of Command View EVA 7.

According to the compatiblity matrix here:

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01080781/c01080781.pdf

that *implies* this feature can be used on older arrays. It would be nice to know for definite.

The user guide for CV EVA 7, doesn't mention any specifics for operating systems, other than "Make sure your host operating system can handle changes in volume size before you change the underlying virtual disk size. Changing the size on some operating systems can cause instability or data loss."

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01081029/c01081029.pdf

Personally reducing the size of a LUN sounds very dangerous. The EVA knows nothing about the file system on the VDisk. I suspect things could get very messy !

Hope this helps,

Regards,

Rob

[Uwe Zessin · Accepted solution]

I've been told some time ago that this feature was intended for Windows Server 2008 (Longhorn) and not be exposed to CV.

It makes sense to generally release it if you want to re-use part of the allocated disk storage and not undergo a full Vdisk deletion/create cycle, but I agree that it is very, very dangerous. No doubt that we will hear some crys for help in the future ;-)

[Uwe Zessin]

The shrink code is in XCS V6.100, so it should work on all EVA 4x00, 6x00 and 8x00 models. I have no information, but I doubt that it will be backported to VCS.

> Anyone know if there are any plans for LUN size reduction on non-MS systems (in particular Openvms).

Time will tell, but I don't think OpenVMS will be given priority.

[Tom O'Toole]

Arg, just the fact that so much high-end kit like EVA ends up being used by MS PC operating platforms says volumes about what's wrong with 'modern' IT. On the other hand, it's really just a nice feature, not a great or essential one.

Of course this feature has to be done in concert with the OS, but if implemented correctly on both ends, it should not be dangerous at all.

[Uwe Zessin]

Tom,
I doubt that somebody from the StorageWorks Division knows what ODS is ;-)

Why not ask the OpenVMS group if they can modify DFG to create free space at the end of the disk - I think it is under their control now, isn't it?

Next, the XQP maintainer needs to add code to shrink the volume size (check for no extents past the end, update the size pointers, shrink the allocation bitmap, ...). Then the OpenVMS and storage people need to work together to build the necessary host agent infrastructure and hey, here we are:
disk shrink on OpenVMS!

[Tom O'Toole]

Agree, it would be mostly up to the VMS folks to grab the ball and run with it....

[Rob Leadbeater]

Hi Tom,

I had the chance to speak to pre-sales the other day.

Current OS support for LUN shrink is only Windows 2003 and the Longhorn beta.

Hopefully other OSs will catch up, assuming HP hasn't completely forgotten about them !

Cheers,

Rob