Exportfs does not accept Knoppix /ramdisk/home

Exportfs does not accept Knoppix /ramdisk/home

[Larry Alkoff]

Please forgive me for bothering you but I and other Knoppix users have a
vexing problem trying to export the Knoppix home directory which is on a
ram disk.

Each time I try to issue
exportfs -rav
an "invalid argument" error message is produced.
However the root / directory is exported without error.

Some background on Knoppix:
Knoppix boots entirely from a cdrom and, in my case, does not use a hard
disk at all.  In fact, there is no hard disk in the Knoppix machine I'm
using now.

Knoppix creates a ram disk when it boots with soft links to the cdrom.
You can delete a soft line to a file and write your own.   In this case
I deleted the soft link to /etc/exports and wrote one for my exports.

Once everything is running satisfactorily you can save the entire /etc
and subdirectories to a thumb drive.

Knoppix boots with a user "knoppix" and its home is mounted as
/ramdisk/home/knoppix
with a symlink
/home -> /ramdisk/home

Tried several variations on below but keep getting an error message.
I suspect that /ramdisk is not considered a file system by exportfs.

This is a portion of /etc/exports:
/       knoppix(sync,rw,no_root_squash)
/ramdisk/home/knoppix   knoppix(sync,rw,no_root_squash)
#/home  knoppix(sync,rw,no_root_squash)

This is the result of exportfs:

root@Knoppix etc # exportfs -rav
exporting knoppix:/ramdisk/home/knoppix
exporting knoppix:/
exporting knoppix:/ramdisk/home/knoppix to kernel
knoppix:/ramdisk/home/knoppix: Invalid argument
reexporting knoppix:/ to kernel

In searching the Knoppix mailing list it appears that others are having
the same trouble trying to mount the Knoppix home directory for NFS.
Some have said that the owner of Knoppix is not interested in NFS, only
Samba.

If I cannot mount using NFS I'll have to go to Samba but am not sure yet
how to go about mounting a Linux share on Samba or whether Samba would
accept the ramdisk part.

Can you tell me why exportfs isn't working with the home ramdisk and
suggest any workarounds?

I have experience with NFS on several Linux machines and have portmap,
nfsd and rpc.mountd running.

I hope the knowledgable people on this list can help solve this puzzle.
Thank you.


-- 
Larry Alkoff N2LA - Austin TX
Using Thunderbird on Slackware Linux


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Re: Exportfs does not accept Knoppix /ramdisk/home

[Neil Brown]

On Monday June 13, labradley@mindspring.com wrote:
> 
> Can you tell me why exportfs isn't working with the home ramdisk and
> suggest any workarounds?

I assume it is actually a tmpfs rather than a regular filesystem on a
true ramdisk ? (what does 'cat /proc/mounts' show?)

A tmpfs doesn't have a stable identifier (like a device number) to use
to identify the filesystem.  You need to give it one.
Try adding
   fsid=27
to the export options for the problematic filesystem. e.g.

/ramdisk/home/knoppix   knoppix(sync,rw,no_root_squash,fsid=27)

NeilBrown



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Re: Exportfs does not accept Knoppix /ramdisk/home

[Larry Alkoff]

Neil Brown wrote:
> On Monday June 13, labradley@mindspring.com wrote:
> 
>>Can you tell me why exportfs isn't working with the home ramdisk and
>>suggest any workarounds?
> 
> 
> I assume it is actually a tmpfs rather than a regular filesystem on a
> true ramdisk ? (what does 'cat /proc/mounts' show?)
> 
> A tmpfs doesn't have a stable identifier (like a device number) to use
> to identify the filesystem.  You need to give it one.
> Try adding
>    fsid=27
> to the export options for the problematic filesystem. e.g.
> 
> /ramdisk/home/knoppix   knoppix(sync,rw,no_root_squash,fsid=27)
> 
> NeilBrown
> 
> 


Thanks for answering my plea for help.
I had tried to contact both you and Olaf Kirch, listed as exportfs 
maintainers in the man page, but in both cases my emails bounced.
In your case the bounce message was:
     SMTP error from remote mailer after MAIL 
FROM:<labradley@mindspring.com>:
     host tone.orchestra.cse.unsw.edu.au [129.94.242.59]:
     550 Sorry, that From address is rejected

I fully expect that the reply to your To: address in au will bounce 
also.  Do you have a really tight whitelist or does unsw hate 
mindspring.com?


The good news - I tried your line exactly as above and
exportfs -rav
worked as expected.

Bad news - for some reason I'm getting the error message:
Mounting knoppix
mount: RPC: Remote system error - No route to host

I've seen that before but it was always fixed by making sure
portmap, nfsd, mountd and statd were running.

They are running on both machines except that on knoppix it's
just "portmap" and on my normal Slackware machine it's "RPC.portmap" 
plus a new one "RPC.quotad".

It's been a while since I fooled with nfs.  Do I need entries in fstab?

You were correct about a tmpfs and
here are my cat /proc/mounts and cat mtab from Knoppix:

cat /proc/mounts
----------------
rootfs / rootfs rw 0 0
/dev/root.old / ext2 rw 0 0
/proc /proc proc rw,nodiratime 0 0
/sys /sys sysfs rw 0 0
/dev/hdd /cdrom iso9660 ro 0 0
/dev/cloop /KNOPPIX iso9660 ro 0 0
/ramdisk /ramdisk tmpfs rw 0 0
/UNIONFS /UNIONFS unionfs 
rw,noatime,dirs=/ramdisk=rw:/KNOPPIX=ro,debug=0,err=tryleft,delete=all,copyup=preserve,setattr=left 
0 0
/dev/pts /UNIONFS/dev/pts devpts rw 0 0
/proc/bus/usb /proc/bus/usb usbfs rw 0 0
automount(pid2172) /mnt/auto autofs rw 0 0


cat /etc/mtab/dev/root / ext2 rw 0 0
-------------------------------------
/dev/hdd /cdrom iso9660 ro 0 0
/dev/cloop /KNOPPIX iso9660 ro 0 0
/ramdisk /ramdisk tmpfs rw,size=399824k 0 0
/UNIONFS /UNIONFS unionfs rw,noatime,dirs=/ramdisk=rw:/KNOPPIX=ro 0 0
/dev/pts /dev/pts devpts rw 0 0
/proc/bus/usb /proc/bus/usb usbfs rw,devmode=0666 0 0
automount(pid2172) /mnt/auto autofs 
rw,fd=4,pgrp=2172,minproto=2,maxproto=4 0 0


Larry

-- 
Larry Alkoff N2LA - Austin TX
Using Thunderbird on Slackware Linux


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Re: Exportfs does not accept Knoppix /ramdisk/home

[Neil Brown]

On Tuesday June 14, labradley@mindspring.com wrote:
> 
> 
> The good news - I tried your line exactly as above and
> exportfs -rav
> worked as expected.

Excellent.

> 
> Bad news - for some reason I'm getting the error message:
> Mounting knoppix
> mount: RPC: Remote system error - No route to host
> 

maybe portmap is being run with "-i 127.0.0.1", meaning "only listen
on the loopback interface".
If so, try running as just plain "portmap".

> I've seen that before but it was always fixed by making sure
> portmap, nfsd, mountd and statd were running.
> 
> They are running on both machines except that on knoppix it's
> just "portmap" and on my normal Slackware machine it's "RPC.portmap" 
> plus a new one "RPC.quotad".

The name differences are purely cosmetic.

> 
> It's been a while since I fooled with nfs.  Do I need entries in
> fstab?

No.

NeilBrown


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