pwd.db too big for / partition

[Marcelo Maraboli]

Tamouh H. wrote:
>> On Mon, Mar 19, 2007 at 10:39:18AM -0700, Chuck Swiger wrote:
>>
>>> On Mar 19, 2007, at 7:54 AM, Marcelo Maraboli wrote:
>>>> my / partition has only 73.196 Mbytes available and since I have 
>>>> 22.000 users, I now cannot change anyone?s password..
>>>>
>>>> root at server:~$ passwd marcelo.maraboli Changing local password for 
>>>> marcelo.maraboli New Password:
>>>> Retype New Password:
>>>>
>>>> /: write failed, filesystem is full
>>>> pwd_mkdb: write old: No space left on device
>>>> passwd: pam_chauthtok(): error in service module
>>>>
>>>> How can I rezise the "/" partition or move the spwb.db and pwd.db 
>>>> files to another partition ?? (each of them is 44 Mbytes)
>>> You certainly don't want to move the password files out of /etc-- 
>>> you'll render the machine unbootable as it needs to find 
>> them on the 
>>> root partition.  The only approach I see which is likely to be 
>>> workable would be to backup the system, repartition the 
>> disks with a 
>>> larger root partition, and restore from backups.
>> I agree.
>>
>>> However, in theory, if you had free disk space, you could 
>> use growfs 
>>> to expand the root partition without repartitioning, but I 
>> am dubious 
>>> about using that command against /.
>> I believe, with growfs, the space that you add must be contiguous
>> with the partition it is joining.   So, unless there is a partition
>> that could be shrunk next to root, (maybe swap is there) it 
>> wouldn't work.
>> If there is room - maybe by mucking with swap if it is the 
>> next partition, then it might be do-able.  But, I would also 
>> be leary of doing it with /.
>>
>> ////jerry
>>
>>> --
>>> -Chuck
> 
> Well, I had a VM laying around so thought to fire it up and do some testing. I know this is absurd abit but I wanted to see the effect of doing symlinks with pwd.db files.
> 
> - I was able to copy /etc/pwd.db /etc/spwd.db to /var/etc/  
> - Then I deleted /etc/pwd.db and /etc/spwd.db
> - created ln -s /var/etc/pwd.db /etc/pwd.db   and ln -s /var/etc/spwd.db /etc/spwd.db
> - changed the root password, worked!
> - Even rebooted the system and was able to successfully able to login
> - All worked fine except, I noticed after running passwd to reset a user password, the system copied pwd.db and spwd.db over the symlinks so I always was ending up with /etc/pwd.db and /etc/spwd.db  files
> 
> I guess this method will solve your space problem if there is a way to make the system follow the symlink instead of overwriting it everytime a password is changed/created.
> 
> Tamouh
> 
> 
Thanks Tamouh for the test !

I did think of this, but after testing WHY changing a password resulted
in "no space available", I realized that FreeBSD updates the
/etc/master.passwd file, makes a backup copy of the 2 .db files,
then runs "pwd_mkdb", which creates new .db files and finally it
erases the 2 backup .db.

So, since each .db is 44Mbytes, in the middle of the process I
have 4 x 44 Mbyte files which cannot fit into 73Mbytes available space.

Since it remakes the .db files, it steps on top of your symlinks....

I'm realizing that I'll have to install the system again in
a separate disk, and then plug it into my server and mount the
original disks as other partitions and copy the config files..

thanks.
-- 
MSc. Marcelo Maraboli Rosselott
Jefe Area de Redes y Comunicaciones  (Network & UNIX Systems Engineer)
Ingeniero Civil Electronico, CISSP  (Electronic Engineer, CISSP, MSc.)

Direccion Central de Servicios Computacionales (DCSC)
Universidad Tecnica Federico Santa Maria         phone: +56 32 2654071
Chile.    http://www.usm.cl                 http://elqui.dcsc.utfsm.cl