Software RAID on VMS

[Vladimir Fabecic]

Thanks everybody.
Hein is right. I did not describe the intented use.
That cluster (2 x ES80 with 24GB RAM each and later some other machines) will have to run many (about 20) Oracle databases. So it will use large files and will need much I/O. And customer demands that file system would be ODS2 (maybe I will change that).
As I said, they have EVA with 60 disks in disk group on other location. They would like to have performance like they have with EVA.

[Bill Hall]

Vladimir,

We migrated off HSG80 and HSJ50 controllers to an XP1024 in February 2003 (VMS V7.3-1). At that time, only Open-E LDEVs (approx. 13-14 GB) were tested and documented as supported by the XP support group on VMS.

We had been using volumes of 60 to 100GB at the time. We could not go back to managing hundreds of small volumes (not to mention we have at least one data file that is typically in the 16GB+ size and wouldn't fit on an Open-E) so we bought RAID licenses for our systems.

Our XP1024 was configured with a large number of 7D+1P array groups. The array groups broken into Open-Es (13-14GB each). Most of our Open-Es are bound as 6 member RAID-0 sets. Each of the member Open-Es are from a different array group on the XP. RAID of course allows you to tailor your chunk size as you see fit.

We also have a "low end" XP10000. It was purchased with only one ACP and we were told it only supports four disk array groups. We were told we would have to purchase another ACP to use any of the eight disk array groups.

Bill

[Robert Gezelter]

Vladimir,

While you are engaged in reconfiguring your disk farm, consider that the conversion can be done without interrupting availability.

Host Based Shadowing can be used to continue operations uninterrupted, a usage that I spoke on at the HP Technology Forum in Orlando, Florida last year. The slides from that presentation can be found at http://www.rlgsc.com/hptechnologyforum/2005/1146.html

Bound volume sets remain a useful feature, but not as useful when physical volume sizes were far smaller.

- Bob Gezelter, http://www.rlgsc.com

[Jur van der Burg]

Re Guenther

>We tried Sw-Raid out of LD devices, which
>gives some errors from time to time (currently
>under inverstigation from the LD maintainer,
>but HP refused to look into that)."

>"Mr. HP" may have refused. I discussed it
>(problem with IO$_NOP) with Jur and it has
>been fixed on both ends (LD amd RAID SW). If
>there's more I am all ears.

Karl is already running LD V8.2 which should fix these issues. I asked him for traces to get to the bottom. HP may not support LD, but I do. If Hostbased raid is involved I know where to find you....

Jur.

[EdgarZamora_1]

We did some extensive performance testing (Rdb databases) on GS1280 with XP12000 using Raid software stripesets out of LD devices. This was recommended by our HP Platinum team. The bottom line results were that performance was just a little bit less than what we were getting out of the EVA5Ks (Raid-1 on the backend). I would say that the combination of using HP Raid software and LD disks was a viable solution for storage coming out of the XP box.