🚀 go-pugleaf

Original Question:
We have an Ultrix system running ULTRIX V4.4 (Rev. 69) System #59: Mon Feb
27 17:43:19 +1000 1995 UWS V4.4 (Rev. 11) which is used as a news server.
Have recently set aside an rz28 for the purpose of news and we're now
running out of inodes. Testing on another filesystem using the -i option
to newfs doesn't give us what we want??? Using default(2048) we get 22524
inodes and using -i 1024 we still get 22524. Help appreciated. 

This explains:
First of all vanilla newfs...

nurk # newfs -v /dev/rrz2a rz56
Warning: partition table overriding /etc/disktab
/etc/mkfs /dev/rrz2a 131072 54 15 8192 1024 16 10 60 2048 t
Warning: 148 sector(s) in last cylinder unallocated
/dev/rrz2a:     131072 sectors in 162 cylinders of 15 tracks, 54 sectors
        67.1Mb in 11 cyl groups (16 c/g, 6.64Mb/g, 2048 i/g)
super-block backups (for fsck -b#) at:
 32, 13056, 26080, 39104, 52128, 65152, 78176, 91200, 104224, 117248, 130272,
installing boot code
sector 0 boot + 1st level boot = /usr/mdec/bootblks
nurk # mount /dev/rz2a /mnt
nurk # df -i /mnt
Filesystem   Total    kbytes   kbytes   %     inodes   inodes   %            
node         kbytes   used     free     used  used     free     used Mounted on
/dev/rz2a      62527       9   56266     0%        4   22524     0%  /mnt
                                                       ^^^^^

then
with -c #cylinders/group and -i number of bytes per inode changed from 
defaults of 16 and 2048 shown above.

nurk # newfs -v -c 8 -i 512 /dev/rrz2a rz56
Warning: partition table overriding /etc/disktab
/etc/mkfs /dev/rrz2a 131072 54 15 8192 1024 8 10 60 512 t
Warning: 148 sector(s) in last cylinder unallocated
/dev/rrz2a:     131072 sectors in 162 cylinders of 15 tracks, 54 sectors
        67.1Mb in 21 cyl groups (8 c/g, 3.32Mb/g, 2048 i/g)
super-block backups (for fsck -b#) at:
 32, 6576, 13120, 19664, 26208, 32752, 39296, 45840, 52384, 58928,
 65472, 72016, 78560, 85104, 91648, 98192, 103712, 110256, 116800, 123344,
 129888,
installing boot code
sector 0 boot + 1st level boot = /usr/mdec/bootblks
nurk # mount /dev/rz2a /mnt
nurk # df -i /mnt
Filesystem   Total    kbytes   kbytes   %     inodes   inodes   %            
node         kbytes   used     free     used  used     free     used Mounted on
/dev/rz2a      59807       9   53818     0%        4   43004     0%  /mnt
                                                       ^^^^^
Voila! More explanation below.

Thanks to:
***From: Grant Ward <gaward@cssip.edu.au>
***From: George Scott <george@moa.cc.monash.edu.au>
***From: Gary Watts <itugiw@tinker.Levels.UniSA.Edu.Au>
It should be possible by changing the number of cylinders in a cylinder group.
By doing this you will increase the number of cylinder groups and hence the
number of inodes. Total inodes = inodes/cylinder groug * cylinder groups
To do this use the -c option on newfs.

ie

ntx> newfs -N -c 8 -i 512 /dev/rrz2c rz25
Warning: partition table overriding /etc/disktab
Warning: inode blocks/cyl group (48) >= data blocks (9) in last
    cylinder group. This implies 144 sector(s) cannot be allocated.
/dev/rrz2c:     1299024 sectors in 2328 cylinders of 9 tracks, 62 sectors
        665.1Mb in 291 cyl groups (8 c/g, 2.29Mb/g, 2048 i/g)


giving us 565968 inodes as opposed to

ntx> newfs -N  -i 512 /dev/rrz2c rz25
Warning: partition table overriding /etc/disktab
Warning: 414 sector(s) in last cylinder unallocated
/dev/rrz2c:     1299168 sectors in 2329 cylinders of 9 tracks, 62 sectors
        665.2Mb in 146 cyl groups (16 c/g, 4.57Mb/g, 2048 i/g)


299008 inodes obtained using the defaults.

***From: Bevin.Steer@unisa.edu.au
***From: Andrea Zuccollo <andrea@ing.unico.it>
***From: Brian Sherwood <sherwood@esu.edu>
***From: swift@cyyoung.ece.psu.edu
***From: "Philip J. Tait" <b12635@phxase.allied.com>
This is what I used:


Dear Dr. File System,

	I need more inodes for my News spool, but when I try to use the -i 
	option of newfs(8), I still get the same number.  What's wrong?

					Out of Inodes.

Dear Out of Inodes.

	The version of the Berkeley Fast File system used by the
	ULTRIX Operating System has a limit of 2048 inodes per
	cylinder group.  This limit is the constant MAXIPG in the
	include file /usr/include/ufs/fs.h.

	When newfs/mkfs runs it attempts to allocate enough inodes
	so that there are enough for an average file size of 2 KB.
	(bytes per inode = 2048).  When there are enough cylinder
	groups this is easy.  In fact, if the cylinder group is small
	enough, it may not get close to the MAXIPG limit.

	But over the years, disks have gotten bigger.  They have
	more cylinders, more tracks and the tracks have more sectors.
	As a result cylinder groups are larger and it's hard to
	allocate enough inodes to meet the 2048 bytes per inode
	limit, with only MAXIPG available.  Since MAXIPG is fixed
	the effective average file size goes up.

	On a News spool tree, the average file probably is around
	or less than 2 KB.  As a result, these large cylinder disks
	don't have enough inodes for the typical file size, and, more 
	importantly, you can't get more, since you're already at the 
	MAXIPG limit.  At least not easily.

	But there are some solutions available...

	Theme of solutions:

		Inodes are allocated on a cylinder group basis.
		Want more inodes, use more cylinder groups.

	1.  Use fewer cylinders per group, thus getting more groups.
	    See the -c option of newfs(8).

	    Note: On the 2nd hand advice of Gregory Neil Shapiro 
	    (gshapiro@wpi.wpi.edu) there are some disks for which
	    the -c option won't work because mkfs(8) enforces a set 
	    of cylinder group sizes that won't allow reducing the 
	    number cylinders per below the default of 16.  This seems
	    to be the case for the RZ57 and RZ58.

	2.  Use a different file system block and fragment size; 4K/512a
	    instead of the usual 8K/1K.  In the case of News this may work 
	    best.  Since most files are small, using the smaller size may
	    help reflect the smaller average file size.  It may also waste
	    less space in partially filled fragments.

	3.  Lie about the geometry.  If the track length or tracks
	    per cylinder is nice factorable number, reduce one to
	    increase the effective number of cylinders.  By playing
	    games with the factors of the geometry you manage to keep
	    the geometry approximately the same.

	    For some disks this may not matter and you can invent whatever
	    lie you want.  For example; the RZ58 uses zoned based recording
	    (banding).  Depending on where you are on the disk, there will
	    more or less sectors per track.  The single geometry presented
	    by ULTRIX is a convient lie.


--
Alan Rollow				alan@nabeth.cxo.dec.com

--


Regards, Kent Adams, System Unit Manager, Computer Centre, JCUNQ
   .O         O	Kent Adams		email:	Kent.Adams@jcu.edu.au
  o/ O       O	Phone:+61 77 814255	Snail:  Computer Centre
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