[Info-vax] 'Partitioning' raid controller for VMS on Integrity

[Bob Gezelter]

On Wednesday, September 8, 2021 at 8:06:12 PM UTC-4, Rich Jordan wrote:
> VMS doesn't do partitions. Are there any SAS type RAID controllers for RX servers that can present 'partitioned' logical drives to VMS so it sees separate spindles? 
> 
> Wondering if it is possible at all to f/ex build a 4 disk ADG array and present more than one spindle to VMS from it. 
> 
> Thanks

Rich,
. 
WADR, IMO the question is not "can a disk be partitioned", but rather, "Can a disk be divided logically with several different  file systems?"

The answer is undoubtedly "Yes", on two different levels.

As has been mentioned earlier in this thread, the last several generations of external storage arrays have supported "logical volumes" which are storage BLOBs of indeterminate composition (non-RAID, RAID-0, RAID-1, ... ). 

Outside the hardware space, OpenVMS has a are multiple choices within a volume and collections of volumes.

The original supra-volume solution was and is FILES-11 volume sets. Supported since the beginning, and still useful for a variety of purposes.

Host-based Volume Shadowing allows the creation of shadow-sets, including single volume shadow sets, which can be expanded dynamically for various purposes, e.g. volume changeover, volume expansion, and backup.

There is also the LD facility, which allows one to create virtual volumes within an overarching volume structure, which can be used to effectively "partition" a disk volume, e.g. create a logical disk, then make the file contiguous. I have used this "file system within a file system" to create disks with different cluster factors for different uses, e.g., one file system for sources, command files, and other user programs, with a relatively small cluster factor, side by side or within a file structure with a 
cluster factor more attuned to large (multi-gigabyte) database or other files.

One can also play mix-and-match with the facilities in various ways, depending upon your goal.

Outside of the Hobbyist world, it is a good idea to document what was done, and more importantly WHY it was done.

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