[Info-vax] bound volume set limits

[Jan-Erik Soderholm]

Den 2017-07-04 kl. 14:22, skrev abrsvc:
> On Monday, July 3, 2017 at 10:38:01 PM UTC-4, David Froble wrote:
>> mcleanjoh at gmail.com wrote:
>>> On Tuesday, July 4, 2017 at 10:04:35 AM UTC+10, Hans Bachner wrote:
>>>> Jan-Erik Soderholm schrieb am 03.07.2017 um 23:48:
>>>>> Den 2017-07-03 kl. 19:19, skrev Baldrick:
>>>>>> [snip]
>>>>>> 
>>>>>> Scenario is this, VAX VMS 7.1 with just under a terabyte and a
>>>>>> half of tape archived data of lots of relatively small files. 
>>>>>> [snip]
>>>>>> 
>>>>> Maybe I'm just missing something here...
>>>>> 
>>>>>> 30 presentations of 50 gig.
>>>>> 
>>>>> Would not 15 x 100 GB, or 5 x 300 GB work?
>>>>> 
>>>>> But maybe 50 GB is at some limit for the OS versions used (?).
>>>> I don't know the details, but "lots of relatively small files"
>>>> might be the key. The maximum number of files allowed on a disk
>>>> depends on the cluster size used:
>>>> 
>>>> $ HELP INITIALIZE /MAXIMUM_FILES [...] Restricts the maximum
>>>> number of files that the volume can contain. [...]
>>>> 
>>>> The maximum size you can specify for any volume is as follows:
>>>> 
>>>> (volume size in blocks)/(cluster factor + 1) [...]
>>>> 
>>>> As increasing the volume size increases the cluster size, a
>>>> bigger volume doesn't buy you much in terms of allowed number of
>>>> files.
>>>> 
>>>> As the limit is applied to the individual volume set member (not
>>>> to the volume set), more files can be placed on a volume set than
>>>> on a single larger volume.
>>>> 
>>>> Hans.
>>> 
>>> Good point Hans, but what's the file sizes and disk block wastage
>>> (i.e. unused blocks at the end of disk clusters), and what's the
>>> distribution of the wastage? For example, if 90% of files use just 1
>>> block and the disk cluster size is 7 blocks ...
>>> 
>>> Another option that might be possible is to swap many small files
>>> for fewer large files, but that will mean changes to the software,
>>> probably not only that which writes to disk but anything that reads
>>> those small files fom disk.
>>> 
>>> Running a museum piece like a Vax on VMS 7.1 isn't advised.  If
>>> support and maintenance costs are involved, a new integrity box will
>>> pay for itself inside 12 months (and maybe depreciable for tax
>>> purposes).  Or if it's a question of waiting for VMS on mass
>>> chipsets then maybe a simulator would be bridging solution.
>> 
>> Well, we don't know why he's running VAX/VMS, nor do we know if he's
>> already using an emulator.  Regardless, it's VAX/VMS V7.3 or earlier
>> that determines what types of devices can be handled.
>> 
>> Without that information, other configurations cannot be part of this
>> discussion.
>> 
>> It seems to be conventional wisdom (CW) that for say a terabyte disk,
>> or larger, wasted space should not be a concern.  Maybe I'm just old
>> school, but I don't like that CW.
>> 
>> Nor do I have a clue what I'd do with a terabyte of storage, except
>> for backup save sets, which would be rather large files.  But that is
>> just me.
>> 
>> Nor do I have much use for bound volumes.  I'd be looking hard for
>> another option.  Perhaps logical names representing multiple disks.
>> Perhaps other solutions.
> 
> While it is generally true that bound volumes are no longer needed with
> larger disks, there are limitations to VAX that may require them as in
> this instance.
> 
> Lets focus on solving the posted problem rather than going down the
> rathole of larger disk availability.
> 
> Dan
> 

Not trying to go down some hole or so, but... :-)

Can LD disks be mounted as voume sets? Maybe not available on VAX/VMS.
I would guess that it would have the same re-mount issue as with
regular disks anyway. And besides, it seemed as that re-mount was
a solution anyway, so the case might be closed...