MORE INODES: Summary and Another Question

From: Mike Jipping (
Date: Fri Feb 16 1990 - 09:19:58 CST

I guess this question is the most frequently asked on earth! Here is
a summary of what worked for me and ANOTHER QUESTION (so please don't
move on just yet...:-)

Our configuration: A Sun 3/160, running 4.0.3, with a 7053 controller
and a 688 Mbyte SMD disk.

The problem: I needed more inodes and 2048 inodes/group is hardcoded into
kernel code. So more inodes must be milked in more sneaky ways.

What I tried:
  (1) Just halving the number of cylinders / group -- using a -c 8 to
      newfs. No go... because blocksize is 8k, cyl/group must be
      multiples of 16 (because of computations involving the number of

  (2) Bump the blocksize to 4k and the cyl/group to 8. This made it
      past newfs and mkfs, and the file system mounted, but the system
      crashed when any use was made of the file system (e.g., a "cd").
      Reason: on a Sun-3, page sizes are 8k, thus blocksizes must be 8k.

  (3) SOLUTION: Trim the number of sectors the filesystem uses by 1. On
      our disk, we have 67 sectors/track. I built the filesystem with
      66 sectors/track. This allows the cyl / group to be set to 8 with
      the blocksize still at 8k. And -- voila! -- we double our inodes!
      We do indeed lose a few kilobytes, but diskspace was not the issue,
      inodes were!

And now to my new question: I lied to mkfs about the number of sectors
in the partition. However, I DID NOT REPARTITION THE DISK. I simply
mkfs'd and everything seemed OK. Will something sneak up on me? (I'm
obviously trying to avoid extended down time here...). That is, is it pertinent
to do a disk repartition?

Thanks to everyone who responded to me with VOLUMES of material. These

      Mike Jipping Internet:
      Hope College BITNET: JIPPING@HOPE
      Department of Computer Science Voice: Hey!

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