[Open-FCoE] Actual data transfer (FCoE)

Deepak Tawri deepak at netxen.com
Wed Jan 21 11:34:01 UTC 2009


Hi,

Can you try if=/dev/zero instead of if=/dev/null ?
i.e.

dd if=/dev/zero of=/target/mydisk bs=1M count=100 2>/dev/null

Also, what is the output of "ls -l /target/mydisk" ?

thanks,
deepak

hansraj Jadhav wrote:
> Hi Joe,
> 
> Im creating LUNS on the target.
> + This is the command i use:
> 
> *dd if=/dev/null of=/target/mydisk bs=1M count=100 2>/dev/null
> 
> echo "open mydisk /target/mydisk" > /proc/scsi_tgt/vdisk/vdisk
> 
> *+ It shows the size of mydisk as zero.
> 
> Name              *Size(MB)*    Block size  Options         File name
> mydisk            * 0  *               512
> /target/mydisk
> 
> Is this the problem?
> 
> @Robert
> The* fdisk -l* on the inititator shows only the physical disks attached.
> It does not show any other disks.
> I can see the Luns when i do a "cat /proc/scsi/scsi"  &
> I can also see new devices if i do " ls /dev/s* ".
> 
> + Please find the text file below.
> 
> Regards
> Hansraj
> 
> 
> 
> 
> On Wed, Jan 21, 2009 at 12:44 AM, Joe Eykholt <jre at nuovasystems.com> wrote:
> 
>> Robert Love wrote:
>>> On Tue, 2009-01-20 at 21:37 +0530, hansraj Jadhav wrote:
>>>> Hi Joe,
>>>>
>>>> Thanks for your quick response.
>>>>
>>>> I tried out the instructions mentioned.
>>>> + I checked the pause and set the tx and the rx 'on' and autoneg ' off
>> '.
>>>> + I also tried
>>>> dd if=/dev/sdXX of=/dev/null count=100 iflag=direct
>>>>
>>>> dd: reading `/dev/sdc': *Input/output error*
>>>> 0+0 records in
>>>> 0+0 records out
>>>> 0 bytes (0 B) copied, 0.00198219 seconds, 0.0 kB/s
>>>>
>>>> + Please find a text file, captured using tshark.
>>>>
>>> Unfortunately I don't get the attachment. I have two accounts subscribed
>>> to this list and I don't get it on either.
>>>
>>> What does 'fdisk -l' show on the initiator side? If you're seeing dev
>> nodes on the initiator you must be connecting to your target and SCSI must
>> be talking to the LUNs. I'm curious if
>> they're showing any capacity though, fdisk should answer that.
>>
>> Robert, you guessed the problem I think.  The sense
>> says the LBA is out of range, so LUN 0 has no capacity.  This isn't too
>> unusual.
>> Hansraj, maybe you used another LUN number for the disk, but in any case,
>> the problem
>> is on the target side.
>>
>> Here's the end of your trace with my comments:
>>
>>  3  11.083730     01.01.01 -> 01.02.00     FCP SCSI: Read(10) LUN: 0x00
>> (LBA: 0x00000000,
>> Len: 1)
>>
>> 0000  0e fc 00 01 02 00 0e fc 00 01 01 01 89 06 00 00   ................
>> 0010  00 00 00 00 00 00 00 00 00 00 00 2e 06 01 02 00   ................
>> 0020  00 01 01 01 08 29 00 00 00 00 00 00 01 2f ff ff   .....)......./..
>> 0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02   ................
>> 0040  28 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00   (...............
>> 0050  00 00 02 00 08 67 54 bf 42 00 00 00               .....gT.B...
>>
>>  4  11.084619     01.02.00 -> 01.01.01     FCP SCSI: Response LUN: 0x00
>> (Read(10)) (Check
>> Condition) LUN:0x00
>>
>> 0000  0e fc 00 01 01 01 0e fc 00 01 02 00 89 06 00 00   ................
>> 0010  00 00 00 00 00 00 00 00 00 00 00 2e 07 01 01 01   ................
>> 0020  00 01 02 00 08 98 00 00 66 00 00 00 01 2f 4b e0   ........f..../K.
>> 0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 0a 02   ................
>> #                                         sense start 70 key 5
>> 0040  00 00 02 00 00 00 00 1a 00 00 00 00 70 00 05 00   ............p...
>> #     4  5  6  7 addl len a    additional sense code 21
>> #                 8  9  10 11 12 13 14 15 16 17 18 19
>> 0050  00 00 00 0a 00 00 00 00 21 00 00 00 00 00 00 00   ........!.......
>> #      2  3  4  5  6  7  8  9 10 11 12 13 14 15
>> 0060  00 00 00 00 00 00 00 02 00 94 91 51 42 00 00 00   ...........QB...
>>
>>
>>>> Regards
>>>> Hansraj
>>>>
>>>>
>>>>
>>>> ---------- Forwarded message ----------
>>>> From: Joe Eykholt <jre at nuovasystems.com>
>>>> Date: Tue, Jan 20, 2009 at 3:00 PM
>>>> Subject: Re: [Open-FCoE] Actual data transfer (FCoE)
>>>> To: hansraj Jadhav <hansrajpict at gmail.com>
>>>> Cc: devel at open-fcoe.org
>>>>
>>>>
>>>> hansraj Jadhav wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> + Im using the Open FCoE initiator.
>>>>>   Im creating virtual LUNS on the target. and i m also able to see
>> these
>>>>> luns
>>>>>  on the initiator when i do a
>>>>>  cat /proc/scsi/scsi.
>>>>>
>>>>> + Im stuck here, how do i see an actual data transfer from the
>> initiator to
>>>>> the target.
>>>>> + I also tried doing mkfs on the Luns discovered, but it failed after
>> some
>>>>> time.
>>>>>
>>>>>
>>>>>
>>>>> Thanks,
>>>>> Hansraj
>>>>>
>>>>>
>>>> Hi Hansraj,
>>>>
>>>> First, be sure you have Ethernet link pause autonegotiated or
>>>> turned on for both nodes and a point-to-point connection
>>>> with no switch in the middle unless it supports lossless behavior
>>>> (very few do).  You can check pause with 'ethtool -a ethX'.
>>>> It should show 'tx on rx on' for both sides.  If not, do
>>>> 'ethtool -A ethX auto off tx on rx on'  If your NICs do not support
>>>> pause, you could very well have data transfer problems.  Although
>>>> SCSI will retry the operations, if the data overruns, it could
>>>> overrun on the retry attempts indefinitely.
>>>>
>>>> Second, the drives should work just like any other disk device.
>>>> Try doing reads with dd on the disks.  If you do
>>>> 'dd if=/dev/sdXX of=/dev/null count=100 iflag=direct' you will
>>>> get 100, 512-byte reads.  The 'iflag=direct' bypasses the buffer
>>>> cache to make sure they are real I/Os after the first time.
>>>> Of course, substitute your actual drive for /dev/sdXX.
>>>>
>>>> You can switch this around to do writes and test for data integrity.
>>>> I make a random file and then copy it to the drive and
>>>> read it back like this:
>>>>        dd bs=64k count=100 if=/dev/urandom of=/tmp/patt
>>>>        dd bs=64k if=/tmp/patt of=/dev/sdXX oflag=direct
>>>>        dd bs=64k if=/dev/sdXX of=/tmp/read iflag=direct count=100
>>>>        cmp /tmp/patt /tmp/read
>>>>
>>>> Since you had failures, I'm guessing the pause
>>>> issue is the problem.   Let me know how it goes.  If you still
>>>> have problems, you could send a small packet trace during the
>>>> failures gathered with:
>>>>
>>>> tcpdump -i ethX -w trace.cap -s 300 -c 200 ether proto 0x8906
>>>>
>>>>        Joe
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>> devel at open-fcoe.org
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>>
> 
> 
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