[Samba] Re: Multiple client access same file

Chris de Vidal cdevidal at yahoo.com
Sun Feb 23 21:13:08 GMT 2003


Ohh, hmm.  I'll try it at work if I get some time and
see what happens.  I have a Samba benchmark I can run
against one of our unused servers, and I'll try to
have 16 "users" access the same iso copied and mounted
twice, just as you're doing.

I might not get time to do this next week, so in the
mean time, a good troubleshooting technique is to
strip any as many smb.conf options as you can leaving
a file with only a few options (the rest, when blank,
will be defaults).  Then gradually start adding them
in again.

I don't see why Samba should be crashing based on what
you're telling me, and that's how I found our problem
last time we had some really bad Samba corruption.  A
read-only filesystem from a large 650MB file mounted
into another part of the same hard drive really
shouldn't crash.  Of course, I could be very wrong (: 
That's what I hope to find out with my benchmark.

/dev/idal

--- Shane Kennedy <skenn at indigo.ie> wrote:
> That's what I have done. In the case of the 2
> programs I know I have 
> trouble with. I made 2 iso  images of 1 CD. 
> Proga.iso, and Progb.iso, 
> mounted as /mnt/iso/Proga, and b.  I soft link ed
> /mnt/Proga -> 
> iso/Proga.  These are then shared by samba
> "directory=/mnt/Proga"  so 
> they can be mapped and accessed from Windoze as   
> E:  -> \\server\Proga 
>  etc.
> Works fine with 2 clients accessing each share, but
> with total 8, 
> accessing 2 shares (4/share), crashes occur..
> 
> Shane
> 
> Chris de Vidal wrote:
> 
> >--- Shane Kennedy <skenn at indigo.ie> wrote:
> >  
> >
> >>Basically, the application freezes in patches, and
> >>eventually, app 
> >>hangs.  With 8 users accessing 2 identical shares 
> >>(I duplicated the iso, 
> >>mount both of them, and share both), at least 2 of
> >>them are likely to 
> >>have hung within 5 minutes.
> >>    
> >>
> >
> >I'm not sure this would even work well in Windows. 
> >CDs make poor multi-user drives.  As I understand
> it,
> >they work well in single-user applications where
> the
> >head doesn't have to move around much.  I recall
> >someone telling me I'd burn out a CD drive in no
> time
> >if I shared it on an FTP server, and Samba would be
> no
> >different.
> >
> >Instead, Linux (and probably other *nixes) gives
> you
> >the option to copy the contents of a CD to an iso
> and
> >then mount that iso into a loopback device just
> like
> >any other files in your system.  In a nutshell,
> this
> >is how it's done:
> >
> >Make sure your kernel has loop support:
> >depmod -a
> >modprobe -l | grep loop
> >(Nothing?  Try this: grep loop /proc/filesystems. 
> If
> >it's there, it's built into the kernel.  If not,
> >compile it in or as a module.)
> >mkdir /samba/share/cdrom1 (or something like that)
> >(insert CD)
> >mount /mnt/cdrom
> >cd /mnt/cdrom
> >mkisofs -o
> /place/where/you/store/iso/files/cdrom1.iso
> >.
> >(man mkisofs or read the CD-writing HOWTO for
> details
> >or other flags you might need)
> >vi /etc/fstab
> >(add a line like this:)
> >/place/where/you/store/iso/files/cdrom1.iso
> >/samba/share/cdrom1 iso9660 loop=/dev/loop1
> >(all on one line)
> >mount /samba/share/cdrom1
> >
> >Do the same for your other CDs, except you're using
> >/samba/share/cdrom2 and /dev/loop2, and so on.
> >
> >Finally, write shares in /etc/samba/smb.conf:
> >[cdrom1]
> >path=/samba/share/cdrom1
> >[cdrom2]
> >path=/samba/share/cdrom2
> >...
> >
> >You can get fancy with fstab mount options like
> >gid=sambausers and put everyone in this group for
> >read-only.  umask=227 will give r-xr-x--- perms to
> >every file and directory for execution.
> >
> >The caveats are iso files (like CDs) are read-only.
> 
> >This may be to your benefit, as the user can't
> >corrupt, delete, overwrite, modify, trojanize, etc.
> >your programs.
> >
> >Also this takes up 650MB per image (naturally) but
> >with hard drives costing about $1/GB this is hardly
> a
> >problem.  And you can store wayy more images in a
> >server with a 100GB drive than with a bunch o' CD
> >drives.
> >
> >Lastly, the loop module takes an argument to allow
> >more than 8 loopback devices.  modinfo loop or
> Google
> >for details.  You'll also need corresponding
> devices
> >added for your extra loopback devices in /dev
> >(/dev/loopXX), like so:
> >mknod /dev/loop46 b 7 46
> >mknod /dev/loop47 b 7 47
> >mknod /dev/loop48 b 7 48
> >...
> >
> >
> >Hope this helps,
> >/dev/idal
> >
> >__________________________________________________
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> >
> >
> >  
> >
> 
> 


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