Re: FFSv2 vs FFSv1

[mlelstv%serpens.de@localhost (Michael van Elst)]

r.phillips%uq.edu.au@localhost (Ray Phillips) writes:

>I noticed that 6.0.1's sysinst uses FFSv2 for the / file system, even 
>on a 20 GB disk.

>Is it true that FFSv2 is needed for WAPBL?

You need a FFSv2 formatted superblock.


>Is there a Web page or document somewhere that details the 
>differences between FFSv1 and FFSv2?

fsck_ffs(8) gives at least an overview.

FFS1 level 0 = inode 4.2/4.3BSD static table
FFS1 level 1 = dynamic table
FFS1 level 2 = 32bit UID/GID, compact symlinks
FFS1 level 3 = free segment maps
FFS1 level 4 = FFS2 style superblock (allows WAPBL)

FFS2 level 5 = 64bit addresses, 64bit timestamps, birthtime, ext attributes

If you format a new filesystem the default is now level 4 for FFS1
and level 5 for FFS2. I.e. the filesystem supports WAPBL.

If you have formatted a filesystem with an older NetBSD with level 3
then you can use fsck_ffs to upgrade the superblock and reach level 4.


>What's the most convenient way of seeing if an existing partition is 
>FFSv1 or v2?

dumpfs -s reports

| % dumpfs -s  /
| file system: /dev/rwd0a
| format  FFSv1
          ^ the filesystem format
| endian  little-endian
| magic   11954           time    Sun May  5 12:46:08 2013
| superblock location     8192    id      [ 4961db97 41fb0303 ]
| cylgrp  dynamic inodes  4.4BSD  sblock  FFSv2   fslevel 4
          ^ table format  ^ inode format  |       ^ the filesystem level
                                          ^ the superblock format

Older dumpfs -s show

% dumpfs -s /
file system: /dev/rraid0a
endian  little-endian
magic   11954 (UFS1)    time    Sun May  5 08:46:18 2013
               ^ the filesytem format
superblock location     8192    id      [ 441b1c12 2ebf670a ]
cylgrp  dynamic inodes  4.4BSD  sblock  FFSv2   fslevel 4
        ^ table format  ^ inode format  |       ^ the filesystem level
                                        ^ the superblock format

% dumpfs -s /d/0
file system: /dev/rraid1a
endian  little-endian
location 65536  (-b 128)
magic   19540119 (UFS2) time    Sun Apr  7 07:48:33 2013
                  ^ the filesytem format
superblock location     65536   id      [ 44133e26 3278a162 ]
cylgrp  dynamic inodes  FFSv2   sblock  FFSv2   fslevel 5
        ^ table format  ^ inode format  |       ^ the filesystem level
                                        ^ the superblock format

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."