topic Re: Max. files on disk in Operating System - OpenVMS

Max. files on disk

Fabian Kempers_1 — Wed, 16 Nov 2005 05:25:20 GMT

I would like to INIT a disk for a lot of file, but I can't seem to get more than 16711679 as maximum number of allowed files.
I've tries to increase/decrease clustersize, max headers, max files...

Is this an VMS limit?

Re: Max. files on disk

Ian Miller. — Wed, 16 Nov 2005 05:49:22 GMT

On what vesion of VMS? There where relevant changes in V7.2

Re: Max. files on disk

Uwe Zessin — Wed, 16 Nov 2005 05:56:10 GMT

The file index number is a 24-bit value.

16711679 = 0.FE.FF.FF(16)

Re: Max. files on disk

Fabian Kempers_1 — Wed, 16 Nov 2005 06:00:40 GMT

OpenVMS 7.3-2

Re: Max. files on disk

Daniel Fernandez Illan — Wed, 16 Nov 2005 06:52:29 GMT

Hi.

The maximum size you can specify for any volume is calculated as follows:

(volume size in blocks)/(cluster factor + 1)

You can modify cluster factor and increase max files.
Saludos.
Daniel.

Re: Max. files on disk

John Gillings — Wed, 16 Nov 2005 20:59:45 GMT

Fabian,

As you've discovered, the current ODS-2 and ODS-5 architectural limit on maximum files allowed on a simgle volume is 2^24-2^16-1 = 16711679

Engineering is aware that the limits of existing file systems is rapidly being overtaken by available technology. What they need is to know what customers need, with business cases to justify the engineering work to extend those limits that need extending (in other words, show them the money!).

In the mean time, you can make it appear there are many more files on a disk using search lists.

$ DEFINE MYDISK DISK1,DISK2,DISK3,DISK4

Make sure all disks have similar directory structures on them, and "rotate" the search list to distribute files.

Re: Max. files on disk

Willem Grooters — Thu, 17 Nov 2005 05:16:22 GMT

[quote]
In the mean time, you can make it appear there are many more files on a disk using search lists.

$ DEFINE MYDISK DISK1,DISK2,DISK3,DISK4

Make sure all disks have similar directory structures on them, and "rotate" the search list to distribute files.
[/quote]

We tried a similar trick once to "enlarge" a disk, but ran into trouble:

$ DEFINE MYDISK DISK1:[DIR1.DIR2.], DISK2:[DIR1.DIR2.]/TRANS=CONCEALED

and DIR3.DIR existed on each DISKn[DIR1.DIR2]; The contents of course was different (newest written on DISK1:[DIR1.DIR2.DIR3].
But when the application tried to access MYDISK:[DIR3]FILE.DAT (the file exists on DISK2:[DIR1.DIR2.DIR3]) RMS returned File not Found. Tracking down the reason, it as found that when reversing the searchlist, the problem was gone. The solution was to keep each base directory (DIR3, DIR4 etc, on the same level) on one disk only.

Re: Max. files on disk

Fabian Kempers_1 — Thu, 17 Nov 2005 08:01:23 GMT

Thans all for the info.