MSA1000 maximum units/Luns?

[Peter Zeiszler]

I am inheriting helping support an environment that has a MSA1000 as its storage. There is plans in work to add 3 new servers to the MSA1000. Current environment is 2 VMS servers attached with 31 units/luns being presented to the VMS.
Someone on a conf call last night said that the MSA1000 had a maximum of 32 units it can present.
I can't find this in the msa100 user guide or the cli guide.
Does anyone know if this is true and what document contains that information?

Looking into this because if it is true then I have to reconfigure the current environment to be able to add the new VMS servers.

[Hein van den Heuvel · Accepted solution]

There are probably several places where this is documented. My first hit was in the QUICKSPECS:

receipts@boynerewards.com


Drives Supported Up to 42 drives
Maximum Capacity 12TB (42 drives x 300GB)
Logical Drives (LUN) Up to 32 Logical Drives
Maximum Logical Drive size 2.0TB


http://h18000.www1.hp.com/products/quickspecs/11033_div/11033_div.html

Too often I see Logical units being 'sized' on the quaint notion that 50GB or 200GB is a 'nice number' and that all LUN shall have the
size. Why?
Embrace the striping! Make'm big! Make'm as you need them, not restricted by some odd number ( 2.0 TB, the max, is not odd :-)

fwiw,
Hein

[Richard Brodie_1]

It appears to be true from the sales stuff:

http://h18000.www1.hp.com/products/quickspecs/11621_div/11621_div.html

[Bill Hall]

Peter,

The maximum number of LUNs is 32. You can find it in this Product Overview at http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c00358098〈=en&cc=us&taskId=101&prodSeriesId=377751&prodTypeId=12169.

It's also in the SAN Design Reference Guide part 3, http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c00310436/c00310436.pdf.

Bill

[Peter Zeiszler]

Thanks guys.

[Hoff]

You could also look to move to DAS controllers (current-generation PCIe stuff is faster than the FC in this old SAN gear) and (where applicable) shadow the shared storage with the other boxes or with this old MSA SAN box; this if you've got GbE or preferably 10 GbE NICs. If you're lacking PCIe and (fast) DAS and (10 GbE) here, you might well be able to scrounge an EVA here for small outlay; the (used) EVA-class widgets are dropping in price. (The MSA1500 upgrade path won't help here as that too is limited to 32 logical units.)

[Peter Zeiszler]

Limited funds for the project. So one follow up question since I haven't had to do this. If I create a HUGE disk (i.e. 1T) how do I partition that into smaller drives?
We still use ODS-2 so have to be aware of block sizes (yes - I know - old stuff).

[Bill Hall]

No cost options would be to use rooted logicals (logical roots) or use the LD driver. The some cost option would be to use HP RAIDSoftware forOpenVMS. I believe you can create a single member array with up to 64 partitions.

Bill

[Hoff]

Presuming you're not on an ancient OpenVMS version, both ODS-2 and ODS-5 file systems will correctly address one-tebibyte disks.

It's not until you're looking to upgrade to 1.5 and 2.0 terabyte disk spindles (or present similarly-sized synthetic disks) that this one-tebibyte addressing limit is (again) a problem.

The upcoming V8.4 release will reportedly allow 2.0 terabyte disk spindles; I'd expect that addressing limit will probably technically be two tebibytes.

Within the one tebibyte spindles (real disks or synthetic), you can probably most easily use concealed rooted logical names. Or yes, you can host-partition using LD or such.

[Steve Reece_3]

Yes, it's limited to presenting 32 LUNs. Remember also that the maximum partition size with VMS 8.3 and below is 1TB - if you have a partition bigger than that VMS won't understand it properly.

You could use the LD driver to create smaller partitions and you could use rooted logicals. You could also use the SW-RAID layered product, but that adds to complexity, cost and CPU overhead in doing disk IO (since the CPU on the VMS box has to work out where to write the data.)

When I was using these things (MSA1000s) day in, day out, I tended to size things for what my clients needed. They didn't need three 1TB disks. They typically needed a disk to boot from (maybe 100GB), a disk for command procedures and logs (maybe 5GB) and the rest was split into the big volumes that they needed.

Whilst others may say, "don't be scared, embrace the striping/raid and make big volumes", that's not the only way and may not be suitable for your site. I would advocate create the right size disks on the MSA1000 and not let logical disk drivers, rooted logicals and any other that stuff get in the way. The LD Driver isn't supported by HP, it's there as an offering that may be of benefit if I remember rightly. Rooted logicals are supported, but can lead to a mess if you don't realize what you're doing. Use the MSA1000 for what it was intended by presenting the right size disks for the right job.

Steve