Re: CIFS and data integrity ; Sorry for the noise

2012-07-31 Thread Celejar
On Tue, 31 Jul 2012 01:15:28 + (UTC)
Mark Fletcher mark2...@gmail.com wrote:

...

 compatibility. I have heard of people wresting their NAS out of the grasp of 
 the OS it comes with and installing Linux on it, presumably by mucking about 
 with firmware etc, but I have never attempted to do any such thing as I would 
 probably screw it up :-) So it is running whatever it was running when it 
 left 
 the factory.

IIUC, NAS hacking is usually done to units that ship with linux, just a
locked down / semi-proprietary version. The hacking enables the unit to
run some more or less standard distribution.

Celejar


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Re: CIFS and data integrity ; Sorry for the noise

2012-07-30 Thread Paul E Condon
On 20120730_122543, Paul E Condon wrote:
 On 20120730_065640, Mark Fletcher wrote:
  Joe joe at jretrading.com writes:
  
   
   On Mon, 30 Jul 2012 01:50:14 +0900
   Mark Fletcher mark27q1 at gmail.com wrote:
   

It looks like what got stored on the NAS is not exactly what was
originally on the host. This is a huge problem for me as it means I
can't rely on backups dumped on that device. Is there something wrong
with the way I am mounting the NAS that is leading to this?

   
   Probably. I'd guess it is a matter of permissions. If you create the
   archive elsewhere, copy it to the NAS, copy it back again, presumably
   there is no difficulty. I also use a Buffalo NAS, but my backups are
   created on my server, then copied. It is possible that if the
   compression and expansion is done on the NAS, that a temp file involved
   may not have the correct permissions to write, or more likely, amend.
   But is your backup not running under cron as root?
   
  
  I put the exact commands I was executing in my original post. There's no job
  involved, I am typing these commands at the command prompt. I'll bring a job
  into it once it works reliably. If you read my original post, you can see I
  create the archive on the host's local disk, test it to make sure it is 
  good,
  and then copy it to the NAS in a separate operation. I use the cp command 
  to do
  the copy.
  
  I'm inclined to rule out a bug in the cp command, which leaves something 
  about
  the way the data is being transferred to my NAS. Hence my concern about 
  whether
  my mount command (again, see details in my original post) was correct.
  
  And yes, to answer someone else's question, this is reproducible, reliably,
  every time. The copy on the NAS is always the same length as the copy on the
  host's local disk, but diff says they are two different binary files and 
  the one
  on the NAS cannot be extracted.
  
 
 A quick way to by-pass the permissions issue is to log in as super-user root, 
 and type your commands and tests as root. As I understand it, root is 
 unstoppable.
 That is why it is so dangerous to use it in day-to-day mucking about. A 
 moments 
 inattention and real damaged is done. But... as a test, and you are testing,
 use root.

Having posted this, which I thought was reasonable, I went and looked at the 
archives to see what OP (Mark Fletcher) had written. It turns out that all
of his investigation was done using commands typed in as root. For me, this
thread is a real puzzle. And very scary. 

Mark: How old is your NAS? What brand? Is it likely that it uses Linux-based 
open/free software? What vintage? (best guess).

IMHO, something bad is happening as we rush into the future. Layers of software
can cover bugs in basic functionality. Complexity beyond human comprehension.

-- 
Paul E Condon   
pecon...@mesanetworks.net


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Re: CIFS and data integrity ; Sorry for the noise

2012-07-30 Thread Gary Dale

On 30/07/12 04:09 PM, Paul E Condon wrote:

On 20120730_122543, Paul E Condon wrote:

On 20120730_065640, Mark Fletcher wrote:

Joejoeat  jretrading.com  writes:


On Mon, 30 Jul 2012 01:50:14 +0900
Mark Fletchermark27q1at  gmail.com  wrote:


It looks like what got stored on the NAS is not exactly what was
originally on the host. This is a huge problem for me as it means I
can't rely on backups dumped on that device. Is there something wrong
with the way I am mounting the NAS that is leading to this?


Probably. I'd guess it is a matter of permissions. If you create the
archive elsewhere, copy it to the NAS, copy it back again, presumably
there is no difficulty. I also use a Buffalo NAS, but my backups are
created on my server, then copied. It is possible that if the
compression and expansion is done on the NAS, that a temp file involved
may not have the correct permissions to write, or more likely, amend.
But is your backup not running under cron as root?


I put the exact commands I was executing in my original post. There's no job
involved, I am typing these commands at the command prompt. I'll bring a job
into it once it works reliably. If you read my original post, you can see I
create the archive on the host's local disk, test it to make sure it is good,
and then copy it to the NAS in a separate operation. I use the cp command to do
the copy.

I'm inclined to rule out a bug in the cp command, which leaves something about
the way the data is being transferred to my NAS. Hence my concern about whether
my mount command (again, see details in my original post) was correct.

And yes, to answer someone else's question, this is reproducible, reliably,
every time. The copy on the NAS is always the same length as the copy on the
host's local disk, but diff says they are two different binary files and the one
on the NAS cannot be extracted.


A quick way to by-pass the permissions issue is to log in as super-user root,
and type your commands and tests as root. As I understand it, root is 
unstoppable.
That is why it is so dangerous to use it in day-to-day mucking about. A moments
inattention and real damaged is done. But... as a test, and you are testing,
use root.

Having posted this, which I thought was reasonable, I went and looked at the
archives to see what OP (Mark Fletcher) had written. It turns out that all
of his investigation was done using commands typed in as root. For me, this
thread is a real puzzle. And very scary.

Mark: How old is your NAS? What brand? Is it likely that it uses Linux-based
open/free software? What vintage? (best guess).

IMHO, something bad is happening as we rush into the future. Layers of software
can cover bugs in basic functionality. Complexity beyond human comprehension.
May I suggest that it could be nothing more than a defective network 
card or cable?


It may also be the result of some other hardware error. That's why I 
suggested doing a file cmp on the files and using rsync. I find exactly 
the same problem when backing up to rewritable optical media. You can't 
always trust the writes to work properly. Always to a verify and correct 
if the files are at all important.



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Re: CIFS and data integrity ; Sorry for the noise

2012-07-30 Thread Mark Fletcher
Paul E Condon pecondon at mesanetworks.net writes:

 
 Having posted this, which I thought was reasonable, I went and looked at the 
 archives to see what OP (Mark Fletcher) had written. It turns out that all
 of his investigation was done using commands typed in as root. For me, this
 thread is a real puzzle. And very scary. 
 
 Mark: How old is your NAS? What brand? Is it likely that it uses Linux-based 
 open/free software? What vintage? (best guess).
 
 IMHO, something bad is happening as we rush into the future. Layers of 
software
 can cover bugs in basic functionality. Complexity beyond human comprehension.
 

Paul -- The NAS is a Buffalo LinkStation 4TB NAS configured to do RAID giving 
me 2TB of storage. I bought myself it for Christmas from Amazon.co.jp (I live 
in Japan) at Christmas 2010. I don't know what OS it will be running but doubt 
it will be Linux since Buffalo will be aiming to maximise Windows 
compatibility. I have heard of people wresting their NAS out of the grasp of 
the OS it comes with and installing Linux on it, presumably by mucking about 
with firmware etc, but I have never attempted to do any such thing as I would 
probably screw it up :-) So it is running whatever it was running when it left 
the factory.

I'm simultaneously glad that someone else is as unnerved by this happening as 
I am, and increasingly nervous that the issue isn't inspiring oh that old 
chestnut reaction in list readers... :-)

Mark


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Re: CIFS and data integrity ; Sorry for the noise

2012-07-30 Thread Henrique de Moraes Holschuh
On Tue, 31 Jul 2012, Mark Fletcher wrote:
 Paul E Condon pecondon at mesanetworks.net writes:
  Having posted this, which I thought was reasonable, I went and looked at 
  the 
  archives to see what OP (Mark Fletcher) had written. It turns out that all
  of his investigation was done using commands typed in as root. For me, this
  thread is a real puzzle. And very scary. 
  
  Mark: How old is your NAS? What brand? Is it likely that it uses 
  Linux-based 
  open/free software? What vintage? (best guess).
  
  IMHO, something bad is happening as we rush into the future. Layers of 
 software
  can cover bugs in basic functionality. Complexity beyond human 
  comprehension.
 
 Paul -- The NAS is a Buffalo LinkStation 4TB NAS configured to do RAID giving 
 me 2TB of storage. I bought myself it for Christmas from Amazon.co.jp (I live 
 in Japan) at Christmas 2010. I don't know what OS it will be running but 
 doubt 
 it will be Linux since Buffalo will be aiming to maximise Windows 
 compatibility. I have heard of people wresting their NAS out of the grasp of 
 the OS it comes with and installing Linux on it, presumably by mucking about 
 with firmware etc, but I have never attempted to do any such thing as I would 
 probably screw it up :-) So it is running whatever it was running when it 
 left 
 the factory.
 
 I'm simultaneously glad that someone else is as unnerved by this happening as 
 I am, and increasingly nervous that the issue isn't inspiring oh that old 
 chestnut reaction in list readers... :-)

Well... there is an awlful lot of CIFS and NFS-related fixes in the kernel
stable queue.  Check that.  Also make sure it is not your NIC driver or
memory (or the NAS' memory) that went bad...

-- 
  One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie. -- The Silicon Valley Tarot
  Henrique Holschuh


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Re: CIFS and data integrity ; Sorry for the noise

2012-07-30 Thread Mark Fletcher
Henrique de Moraes Holschuh hmh at debian.org writes:

 
 Well... there is an awlful lot of CIFS and NFS-related fixes in the kernel
 stable queue.  Check that.  Also make sure it is not your NIC driver or
 memory (or the NAS' memory) that went bad...
 

I wondered about this too -- and the defective cable / NIC idea posted by Gary 
earlier. But I would have expected that network card / driver / memory issues 
would result in a failed transfer that would either end in tears (error 
messages) or would cause part of the transfer to be retried and thus take 
longer but eventually end with correct data having been transferred. What's 
giving me the heebie-jeebies (if you'll pardon the technial term) about this 
is that every software and hardware component seems to think that everything 
went swimmingly as far as I can tell, but the data on the target is 
nonetheless not correct.

Mark


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Re: CIFS and data integrity ; Sorry for the noise

2012-07-30 Thread Richard Hector

On 31/07/12 13:15, Mark Fletcher wrote:

Paul -- The NAS is a Buffalo LinkStation 4TB NAS configured to do RAID giving
me 2TB of storage. I bought myself it for Christmas from Amazon.co.jp (I live
in Japan) at Christmas 2010. I don't know what OS it will be running but doubt
it will be Linux since Buffalo will be aiming to maximise Windows
compatibility.


http://opensource.buffalo.jp/gpl_storage.html

I think it quite possibly is :-)

Oldish though - 2.4.20 by the looks of it.

Richard


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