[Info-vax] RAID vs. MOUNT/BIND

[R.A.Omond]

On 19/11/2010 17:54, Wilm Boerhout wrote:
> VAXman- @SendSpamHere.ORG mentioned  on 19-11-2010 13:27:
>> In article<ic5cik$f3i$3 at online.de>, helbig at astro.multiCLOTHESvax.de
>> (Phillip Helbig---undress to reply) writes:
>>> In article
>>> <3843bded-c68a-4d35-9b79-749ff1b8547a at v19g2000yqa.googlegroups.com>,
>>> onedbguru<onedbguru at yahoo.com> writes:
>>>
>>>> I had a customer with an RMS indexed file that was> 40GB using RA90
>>>> (1.2GB),RA72(1.0GB) type of disks in bound volume sets on an 8000-
>>>> class system (maybe an 8600???)
>>>
>>> How many disks can be in a volume set?
>>
>> The file ID (3 words) limits this to 255:
>>
>> {FID$W_NUM},{FID$W_SEQ},{FID$B_NMX at 8!FID$B_RVN}
>>
>> RVN is the relative volume number. When 0, it's a typical mounted volume.
>> When it is non-zero, it represents a volume number in the bound volume
>> set.
>> This can be a value of 1 to 255. (ie. it's an unsigned byte) I've never
>> seen a volume set with 255 volumes but I'm sure that somebody, somewhere,
>> must have tested this close to or at its limits.
>
> This can surely be tested with LD disks. I'll have a go this weekend.
>
> First hurdle will probably be the length of the $MOUNT command in DCL...
> :-)

Nope, that's not a hurdle.  You can mount the individual disks
one-by-one.

Here's an example:

$ ld create x.1/siz=1000
$ ld create x.2/siz=1000
$ ld create x.3/siz=1000
$ ld create x.4/siz=1000
$ ld conn x.1
%LD-I-UNIT, Allocated device is EISNER$LDA14:
$ ld conn x.2
%LD-I-UNIT, Allocated device is EISNER$LDA15:
$ ld conn x.3
%LD-I-UNIT, Allocated device is EISNER$LDA16:
$ ld conn x.4
%LD-I-UNIT, Allocated device is EISNER$LDA17:
$ init lda14: 1
$ init lda15: 2
$ init lda16: 3
$ init lda17: 4
$ mount/bind=x lda14: 1
%MOUNT-I-MOUNTED, 1 mounted on _EISNER$LDA14:
$ mount/bind=x lda15: 2
%MOUNT-I-MOUNTED, 2 mounted on _EISNER$LDA15:
$ mount/bind=x lda16: 3
%MOUNT-I-MOUNTED, 3 mounted on _EISNER$LDA16:
$ mount/bind=x lda17: 4
%MOUNT-I-MOUNTED, 4 mounted on _EISNER$LDA17:
$ sh dev lda14:

Device        Device           Error    Volume         Free  Trans Mnt
  Name         Status           Count     Label        Blocks Count Cnt
EISNER$LDA14: Mounted alloc        0  1                  968     1   1
EISNER$LDA15: Mounted alloc        0  2                  969     1   1
EISNER$LDA16: Mounted alloc        0  3                  969     1   1
EISNER$LDA17: Mounted alloc        0  4                  969     1   1