[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference vaxaxp::vmsnotes

Title:VAX and Alpha VMS
Notice:This is a new VMSnotes, please read note 2.1
Moderator:VAXAXP::BERNARDO
Created:Wed Jan 22 1997
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:703
Total number of notes:3722

466.0. "Maximum_files" by BUSY::BETTRO () Mon Apr 14 1997 11:02

	Anyone know if there is a way to change the maximum # of 
	files on a volume without having to init the device? It
	would really be nice if there was a set vol/maximum_files
	command in the future. In the mean time if anyone knows
	of a way it would really be appreciated!

	Thanks for any help!
	Joe
T.RTitleUserPersonal
Name		DateLines
466.1EPS::VANDENHEUVELHeinMon Apr 14 1997 12:5129
    
    >	Anyone know if there is a way to change the maximum # of 
    >	files on a volume without having to init the device? 
    
    Hmm, I have my 'VMS file system internals (McCoy)' as home so this
    is from memory. The maximum files is not just a number on the disk,
    it is used to create a bitmap from for each possible bit in INDEXF.SYS.
    I suspect that bitmap to be early in Indexf.sys itself, so the max
    in place growth is probably a round up to a block full of bits. (4096).
    
    > It would really be nice if there was a set vol/maximum_files 
    
    Nah... noone needs that except you yesterday and never again.
    The default max file is really generous (and it should be considering
    we are only talking about 1 bit per file.) as it corresponds with
    two clusters per file where the minimum size really is 1 cluster
    plus 1 block per file. I suppose, as cluster sizes are growing, the
    default max files is drifting away from the absolute max max files,
    but a disk filled with 1 cluster files would be fairly rare, and 
    supposedly, however sets up the disk knows what is going on.
    I suspect, but may be wrong, that MAXIMUM_FILES is a knob which is
    rarely turned and then only by folks that really know what they are
    doing. (They may then move on leaving a trap for others ofcourse:-(. )
    
    fwiw,
    	Hein.
466.2MOVIES::WIDDOWSONRod OpenVMS Engineering. Project RockMon Apr 14 1997 13:316
    Hein's right, modulo the absolute max number of files on a volume with
    is the maximum of (4096*64k) [The max size of the bitmap in INDEXF.SYS for
    ODS2] and 2^24 [The max fid size]....
    
    Of course the customer may just be seeing INDEXF.SYS fragmentation. 
    What is the error message being seen ?
466.350836::TLAUER"I've been designed multi-asking."Fri Apr 18 1997 04:2310
re .1:
>     Nah... noone needs that except you yesterday and never again.

But imagine! you could easily save some valuable disk blocks within the index
file bitmap, and provide these as additional general storage to your available
disk space. Just use an artificially low maxfiles value when initializing your
disk, and raise that only when there's a real need... ;-)


-- Thilo
466.4MOVIES::WIDDOWSONRod OpenVMS Engineering. Project RockFri Apr 18 1997 07:343
    You're a very, ahhhh, inventive, person Thilo.
    
    (Ps - Hi !)