Confused over CIFS

Ted Hilts thilts at
Tue Jan 13 05:01:03 UTC 2009

Derek Broughton wrote:
> Preston Kutzner wrote:
>> On Jan 10, 2009, at 8:23 PM, Matthew Flaschen wrote:
>>>> Part way through it got very slow -- and I mean very slow!!!
>>> SMB is not really designed to transfer huge amounts of data.  It's
>>> better to use rsync for that (there are Windows rsync servers), as
>>> you'll get better compression.
>> Just out of curiosity, what is your reasoning that SMB is not designed
>> for transferring huge amounts of data?  SMB/CIFS is the file sharing
>> protocol Microsoft uses in its Windows operating system.  It is
>> designed, in a sense, as Microsoft's alternative to NFS.  If it wasn't
>> meant for large transfers of data, it wouldn't be the primary protocol
>> for file-sharing in Microsoft solutions.
> I really don't see how that follows.  It is basically nothing more than 
> patches on patches since the original LAN Manager of the 80s, and it's 
> entirely possible (though I'm not in a position to say with authority) that 
> it _isn't_ reliable for large data transfers.  What I can say for certain is 
> that large data transfers overs SMB seem to stall with regularity when I 
> try.
>> sudo mount -t cifs //<windows_machine>/<share> /<mount>/<point> -o
>> username=*****,password=*****
> Or better use "credentials=/path/to/file" to give username/password for 
> repeatable mounts.
I've read everything you guys have posted - thanks. I think there are 
issues you have not addressed that were relevant to my particular situation.

1. There are two machines, one is called "misty" (XP Home with NTFS 
formatted disks) and is the FROM machine for the data transfer.  The 
second machine is called "Ubuntu" (Linux Ubuntu 8.4 upgraded from 7.10 
with it's own partition and dual booted with another XP Home machine).  
Note that the  7 hard drives on the Ubuntu machine are NTFS formatted 
disks with one of these partitioned to create the Ubuntu system which is 
all I run on this machine. Ubuntu has direct access to all these NTFS 
formatted drives as part of it's local system. Ubuntu is the TO machine 
for the data transfer and the data will be placed on one those NTFS 
formatted drives.  So the data transfer is moving from "misty" (XP Home 
NTFS drive) to "Ubuntu" (Ubuntu 8.4 NTFS drive).

2. I used traditional "smbmount" not "mount.cifs" although it seems that 
it was CIFS that was engaged in the data transfer when I looked at the 
mounts. The data transfer using "cp" worked very well and fast but went 
almost dead after processing a lot of data so I tried to bring the 
transfer to an end with "Ubuntu"  responding that I should use 
"umount.cifs" which seemed to fail but thinking back was probably just 
taking a lot of time to stop. Why the data flow went very slow could be 
for a number of reasons.  For example it may not have been a failure on 
the part of "cp" or CIFS and then maybe it was cp or CIFS. But I often 
get glitches (I think from my IPS) which have a similar effect on 
running processes in that they almost stop or appear to stop and after a 
while they are running again and in some cases they have to be 
restarted. The data transfer I was running would have taken a long time 
because when I ran it I knew literally nothing about rsync and I was 
using plain old "cp".

3. Does the FROM and TO filelsystem (both being NTFS) have anything to 
do with this data transfer?

4. I have been looking at using backuppc but the man page mentions 
numerous tasks in setting it up. The man page does seem to indicate that 
XP Pro is required and says nothing about XP Home. I should never ever 
got involved with HP Home machines as they are nothing but a big head 
ache when it comes to networking with Linux machines.

Thanks -- Ted

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