Re: Kernel 3.0: Instant kernel crash when mounting CIFS (also crasheswith linux-3.1-rc2

[Steve French]

I did some testing with 3.0 kernel (cifs client) and was getting 90%
wire speeds writing
cifs files to the server (Windows or Samba)

On Thu, Aug 18, 2011 at 11:01 AM, Steve French <smfrench@xxxxxxxxx> wrote:
> Writing from cifs kernel client to WIndows or Samba server should be much faster
> than the reverse (ie large file sequential file copy to server is
> faster than copying
> a file from the server)  cifs kernel client serializes reads from the same file
> (unless mounting forcedirectio, in which case caching is disabled) and uses
> a relatively smaller read size (16K) - while for writes they are sent
> in parallel
> even if to the same file (and the write size is much larger e.g. 126976 bytes,
> and can be set even larger to Samba).  There may be a few cases (such
> as copying to WIndowsXP or Windows7) where timeouts on the
> server slow things down (writing from linux client to Windows XP
> or Windows 7) but what is the server type?
>
>
> On Thu, Aug 18, 2011 at 7:14 AM, Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> wrote:
>>
>>
>> On Thu, 18 Aug 2011, Justin Piszcz wrote:
>>
>>>
>>>
>>> On Thu, 18 Aug 2011, J. R. Okajima wrote:
>>>
>>>>
>>>> Justin Piszcz:
>>>>>
>>>>> Does anyone know if any kernel supports CIFS w/out crashing? I'd like to
>>>>> backup some CIFS shares, thanks.
>>>>>
>>>>>
>>>>> mount -t cifs //w2/x /mnt -o user=user,pass=pass
>>>>>
>>>>> [  881.388836] CIFS VFS: cifs_mount failed w/return code = -22
>>>>
>>>>        :::
>>>>
>>>> Since it failed mounting, this patch will help you. Although the patch
>>>> will fix one bug, there still may exist another problem.
>>>>
>>>> http://marc.info/?l=linux-cifs&m=131345112022031&w=2
>>>
>>> Hi,
>>>
>>> Latest patch (this one) applied to linux-3.1-rc2 works, at least it
>>> mounted
>>> this time and did not instantly crash the kernel!
>>>
>>> I also tried the hostname again (and it did not crash the kernel, but it
>>> failed to mount).
>>>
>>> Used the IP and it mounted successfully:
>>> //10.0.0.11/x          28T  5.0T   23T  19% /mnt
>>> //10.0.0.11/y          19T  1.2T   18T   7% /mnt2
>>>
>>> It has not crashed yet (which is good), I'll apply this patch to my
>>> production machine and test taking backups of this data and let you know
>>> if it crashes again, thanks!
>>>
>>> Justin.
>>
>>
>> Hello,
>>
>> It is working but very slowly:
>>
>> Device eth6 [10.0.1.2] (1/1):
>> ================================================================================
>> Incoming:                               Outgoing:
>> Curr: 37.60 MByte/s                     Curr: 0.44 MByte/s
>> Avg: 4.98 MByte/s                       Avg: 0.09 MByte/s
>> Min: 0.00 MByte/s                       Min: 0.00 MByte/s
>> Max: 40.79 MByte/s                      Max: 0.48 MByte/s
>> Ttl: 1.45 GByte                         Ttl: 26.77 MByte
>>
>> Over 10GbE the other direction (Linux -> Windows (via Samba)) I get
>> 500MiB/s, is CIFS slow?
>>
>> I'll look into options to tweak the speed but this is very poor speed when
>> you have to transfer 5-10TB.  However, it is not crashing anymore, so any
>> speed is better than that :)
>>
>> Justin.
>>
>>
>
>
>
> --
> Thanks,
>
> Steve
>



-- 
Thanks,

Steve
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