related to maxfiles on 39gb disk

[Dipali]

Hi

i have 39Gb disk and there are 837869 max files in it.how i will set maxfiles? is it possible or it is fix for particular disk.open vms version is v7.3-2

Dipali.

[Tanuj Maitra]

You can have a max of x No of files, where
x=(total disk size in blocks/((cluster size+1)*2)).
For more, check the help on /maximum_files, /header & /cluster_size of Initialize.
You can check the cluster size of the disk in question by "sho dev/full " command.
You'll have to initialize the disk for setting the new file limit on the disk, with the new value.

[Tanuj Maitra]

Sorry for the wrong formula in my earlier reply.
The correct formula would be
x=(total disk blocks/(cluster size+1)), which is actually double of the previous value.
The previous value is the default value for max files.

[Karl Rohwedder]

You have to reinit the disk with /MAXIMUM=nnn.
Be sure to specifiy a number which is big enough at all means, it costs nothing.

Besure to also specific /HEADER=nnn. If you have an estimate of how many files will be stored on the disk, use this number as NNN.
So the indexfile gets big enough and must not be extended during operation.

regards Kalle

[Art Wiens]

And if you're INIT'ing, don't forget the /DIRECTORIES value - the initial size of the MFD.

Cheers,
Art

[Dipali]

Hi

the given formula for maxfiles=(total disk blocks/(cluster size+1)), for a 39 GB disk, the max file ( as per formula) comes as: 29283200 (currently it is - 837869).can i set it to its maximum value i.e 29283200.is it create any performance issue? what will be th fragmentation level?

and formula is same for shadow disk? and how to set maxfiles for shadow disk?

[Karl Rohwedder]

Dipali,

setting maximum files to a big value does not cost you anything, see the excerpt from help:

NOTE

The /MAXIMUM_FILES qualifier does not reserve or create
space for new file headers on a volume. The file system
dynamically allocates space as it is needed for new headers.

It just increases a limit.

Other qualifiers like /HEADERS or /CLUSTER
may influence performance and possible fragmentation.

A shadowset is formed using a disk, which has been INITed before, so you do not INIT shadowsets. Other commands, like SET VOLUME work on ph. disks as well as on shadowsets.

regards Kalle