SUMMARY: fsck under 4.1.1

From: davies@gest20.SINet.SLB.COM
Date: Wed Aug 12 1992 - 02:24:12 CDT

CC: davies

firstly, thankyou for all the replies. I received 18 replies from Sun Managers - all of which agreed that what I should really do is upgrade to 4.1.2! However the answer to my question goes as follows.

Original Question:

I would like to implement the quick fsck available under SunOs 4.1.2 on my system that is running 4.1.1. I do not wish to upgrade to 4.1.2 at this time but would really benefit from the advantages of the quicker new fsck.

a> How are the messages "sdx is stable" derived ? Is this the product only of the fsck program or are new disk journaling routines also needed.

b> Is there a patch available to do this and if so which one.



This is done with a special "clean" flag in the file system which is updated by sync when it writes to a disk.

The 4.1.2 kernel maintains the clean/stable flags in the superblock.
Just running fsck won't work (and might even be dangerous as the
old 4.2 fs code might not clear the stable/clean flags).

They come from a new type of filesystem under 4.1.2 that has a "state"
flag. If the superblock is saved properly before the system is
shutdown, the new fsck will produce the "sdx is stable" message.

modify the kernal disk sync routines to set a flag bit the the superblock
to mark the disk as clean when a disk is unmounted.

modify fack to look for this bit.
It requires a change in the kernel (to mark the filesystem as clean
when unmounted).The real work of the quick check feature is implemented by changes to
the kernel to maintain a flag in the superblock that indicates whether
the the file system is stable versus in the middle of being modified.
All the new fsck has to do is look at the flag first, and skip checking
the file system if the flag says it's stable.
Basically the superblock has a new field which marks the filesystem as
clean or unclean. fsck has also been improved to do check filesystems in

A couple of things actually - there are some new flags in the filesystem
that indicate when the filesystem is stable. UFS has been modified to
know about them as has fsck. I suspect you'll need the ufs code from
4.1.2 as well as fsck...


You can get something called quickcheck from your salesdroid for SPARC
only, Sun3 for some reason doesn't have this..
this functionality through Sun's Disk Suite software.

NO patch !
It was an unbundled product up to 4.1.2.
If you have a maintenance contract, may be you can convince your local
sales rep. to give you a copy of the software ?
May be a simple "tar" and not an official installation ???
Ask your Sun salesman what they would charge for
QuickCheck if you don't want to upgrade yet. I think it was on the order of
$300 list price....

for sunos 4.1.1, you can buy the disksuite product, which
includes quickcheck as one of its packages. it's a variety
of changes to the filesystem (that mark the clean flag in
the superblock) and the fsck program.

If I remember correctly, the software was first released under SunOS 4.1
as the unbundled package "Quickcheck". When 4.1.1 came out, there were
enhancements to the filesystem (such as I/O clustering?) that prevented
4.1 Quickcheck from being installed (well, it could be installed to get
a better fsck program, but full installation would disable the enhancements).

So far as I know, the only way to get this under 4.1.1 (in the absence of PD
software for this) is to install the "Disk Suite" product from Sun.

For 4.1, you could get QuickCheck for a nominal fee
(about $100?), and you can install this in 4.1.1, but you then lose the
filesystem I/O clustering introduced in 4.1.1.

you can pay Sun 100 bucks for Quickcheck which is included
for free in 4.1.2.

The quick check functionality is also included in Sun's unbundled
product Online DiskSuite, the primary purpose of which is to support
mirroring and large (>2GB) file systems. This can be installed on
SunOS 4.1.1, but it involves building a new kernel and it is more
expensive than the SunOS upgrade.



>Is there a patch available to do this and if so which one.

I would doubt it, I think sun would claim that this is a 4.1.2 feature.

There was an unbundled product for 4.1.1, but I don't think you
want to buy that. Why don't you want to upgrade to 4.1.2?

yes, the new fsck on 4.1.2 is great. I can reboot a server with 16
disks and 20 partitions in less than 15 minutes.

There is a product available from Sun called "QuickCheck" that provides
the faster fsck for pre-4.1.2 systems. Many people have commented that it was
rotten of Sun to make you pay individually for improvements to the O.S. (instead
of their being bundled in with new releases). I think that's the only reason
4.1.2 includes the faster fsck. Anyway, we bought it some time back for our
server running 4.1 PSR_A. It's worked like a champ! A "reboot" command looks
just like a "fastboot" command now, unless the system went down very hard during
a power failure. Even then, most of the partitions are okay, saving alot of
time during the reboot. *Please* summarize what you find out about this to the list. I use
a 3/60 at home, for which 4.1.1 was the last OS released (as you probably
know). Anyway, I'd love to get the quick fsck on there if possible.

PS: why don't you want to move to 4.1.2? I use it at home without any

The 4.1.2 upgrade really is awfully easy and compatible with EVERYTHING
... try it!?

Simplest solution is to upgrade to 4.1.2.

Casper Dik <>
Frank P. Bresz <>
Ken Nawyn <> (Gerhard Holzer) (David N. Edwards)
stern@sunne.East.Sun.COM (Hal Stern - NE Area Systems Engineer) (HAO Computer System Managment Group) (John Turner)
Peter Shipley <shipley@tfs.COM>
Mike Raffety <> (J. Matt Landrum)
mike%trdlnk@uunet.UU.NET (Michael Sullivan)
glenn%kalli@fourx.Aus.Sun.COM (Glenn Satchell)
kevins%corn.Japan.Sun.COM%fourx%kalli@fourx.Aus.Sun.COM (Kevin Sheehan {Consulting Poster Child})

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