Volume shadowing betwen HSZ80 and HSG80

[Bojan Nemec]

Hi,

I have two DS20e with a double HSZ80 and a DS25 with a HSG80. All three systems have the VOLSHAD license and OpenVMS 7.3-1. Is it posible to create volume shadow sets betwen the HSZ80 and HSG80 devices?

Bojan

[Jan van den Ende]

Hi Bojan.

It depends a bit. Are the devices presented with EXACTLY the same number of blocks after INIT?
Then there is no problem.

But I expect the HSG to hold bigger disks..
Then, it CAN be done since V7.3-2, and there WERE plans to also make this available with a patch kit for 7.3-1, but I don't remember seeing it. Cannot check now, and since we went 7.3-2 I was no longer that much interested in 7.3-1 kits... :-(

So, my guess is that going 7.3-2 will be the way (7.3-1 is soon no longer supported anyway).


hth,

Jan

[Bojan Nemec]

I forgot to say that both disks are 36G but after init they differ for some 100 blocks. Upgrading to 7.3-2 is the last option.

Bojan

[John Eerenberg · Accepted solution]

It is never a problem to go into the controllers themselves and partition the disk so that match exactly.

If you need instructions on how to do that, just let us know. You may have to do it to both but with a little luck, only one controller needs to partition the disk(s).

john

[Anton van Ruitenbeek]

Bojan,

Did you init the disk on a HSG using a 'save on disk' qualifier ?
If so, the disk looses some blocks for information wich you better can not have on the disk. It actualy makes the disk hardcoded in some slot. But this is youre problem :-( . I never do this anymore. Normaly the disks should have the same size on a HSZ and a HSG. Both are (to be honoust) the same controllers only the HSZ is SCSI/SCSI and the HSG is Fiber/SCSI (HSV is Fiber/Fiber).

AvR

[Bojan Nemec]

John,

Yours solution seems great. I will try to test it sooner posible.

Anton,

Thats probably the reason for the size difference. The disks was not initialized by me so I must check.

Points (a lot of them) will arrive after testing!

Bojan

[John Gillings]

Bojan,

Your best option is to install V7.3-2 (from V7.3-1 it's really just a big patch kit! There should be NO application compatibility issues)

You will then enjoy dissimiliar device shadowing (DDS), dynamic volume expansion (DVE), and (with VMS732_HBMM-V0200 due by the end of this week) host based mini merge. DDS was created SPECIFICALLY to deal with the issue of shadowing across different controllers. DVE opens a whole new world of storage management, including the ability to upgrade your storage with ZERO downtime. HBMM will reduce your merge times by orders of magnitude.

Although it *may* be possible to adjust volumes to be precisely the same size, it's very fiddly.

[Fodil ATTAR]

Hi,

May I suggest to have a look to the discussion about HBMM Experience whith WBM_MSG_UPPER dynamic system parameter

especially the 2 lasts messages.

the link is :

http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=686571

Regards,

Fodil.

[Uwe Zessin]

""DVE opens a whole new world of storage management, including the ability to upgrade your storage with ZERO downtime.""

Can you enlarge the header bitmap in INDEXF.SYS with DVE?

[Ian Miller.]

"Can you enlarge the header bitmap in INDEXF.SYS with DVE?"
I think the way this is done is that you can expand a volume up to the limit which is set when the volume is inited. This limit sets the size of the storage bitmap. INDEXF.SYS can grow anyway.

[Uwe Zessin]

I am talking about the file header bitmap, not BITMAP.SYS.

[Keith Parris]

When you create a partition on the controller, use the keyword/parameter BLOCK=nnnn instead of SIZE=nn to specify the size of the partitition. SIZE=nn specifies a percentage of the disk space, whereas BLOCK=nnnn refers to an exact number of 512-byte blocks.

[Keith Parris]

Sorry -- my note above was in response to John's "Although it *may* be possible to adjust volumes to be precisely the same size, it's very fiddly."

I was trying to point out that indeed it *can* be done, and how one does the "fiddly" part.

[John Gillings]

To answer Uwe's question "Can you enlarge the header bitmap in INDEXF.SYS with DVE?", no you can't. However, you CAN expand INDEXF.SYS, and you can expand the storage bitmap.

The default value for MAXIMUM_FILES (and hence the header bitmap) is more the maximum possible number of files on the disk, but is based on the current size, not the expansion limit. If you intend to populate the volume with minimum sized files (ie 1 cluster), then you may need to take this into account when initialising.

Each additional million files will cost you 256 blocks of disk space for the header bitmap, allocated at initialisation time. As is often the case, with forethought, a small investement up front may save you a lot of grief in the future.

[Bojan Nemec]

Hi,

I will try to make the shadow sets Saturday afternoon. The 7.3-2 is still not an option (I think that this is the best solution). So yours responses will help me much.

Bojan

[Bojan Nemec]

Thanks to all,

The problem was solved issuing the INITIALIZE command on the controler.

INITIALIZE container CAPACITY=size

Partitioning was not used because the controlers are in dual-redundant mode and CREATE_PARTITION displays an error that this operation is not allowed when controlers are in dual-redundant mode.

Bojan