Broken pipe on my target. Is there any option on my initiator to fix it?

[Felipe Gutierrez]

Hi, I am using jscsi.org target and open-iscsi initiator. Through NFS I can copy a bunch of files and it seems ok. When I execute a virtual machine from vmware (vmware -> NFS -> open-iscsi -> target jscsi) the target throws a broken pipe some times. THe initiator reestabilish the connection, but this broken pipe is corrupting my VM file system.

On a good work my target sends SCSIResponseParser PDU and after that receives SCSICommandParser PDU from the initiator. When the broken pipe is up to happen the target sends SCSIResponseParser PDU and does not receive SCSICommandParser PDU. Instead of it, the target receives after 5 seconds NOPOutParser PDU, and sends  NOPInParser PDU. After 60 seconds my target receives TaskManagementFunctionRequestParser PDU with OpCode: 0x2, which means to abort the task. So, the target do what the initiator is asking. The broken pipe happens ans a nes connections is estabilished.

My question is, why the initiator does not keep the comunication after the SCSIResponseParser PDU sent by the target? Is there any way to see if this message is wrong? Or any initiator log error?

Here is the target debug.

(228)19:19:01 DEBUG [main] fullfeature.WriteStage - PDU sent 4:   ParserClass: SCSIResponseParser

  ImmediateFlag: false

  OpCode: 0x21

  FinalFlag: true

  TotalAHSLength: 0x0

  DataSegmentLength: 0x0

  InitiatorTaskTag: 0x28000010

  Response: 0x0

  SNACK TAG: 0x0

  StatusSequenceNumber: 0xc8a

  ExpectedCommandSequenceNumber: 0xc6e

  MaximumCommandSequenceNumber: 0xc6e

  ExpDataSN: 0x0

  BidirectionalReadResidualOverflow: false

  BidirectionalReadResidualUnderflow: false

  ResidualOverflow: false

  ResidualUnderflow: false

  ResidualCount: 0x0

  Bidirectional Read Residual Count: 0x0

(273)19:19:06 DEBUG [main] connection.TargetSenderWorker - Receiving this PDU:

  ParserClass: NOPOutParser

  ImmediateFlag: true

  OpCode: 0x0

  FinalFlag: true

  TotalAHSLength: 0x0

  DataSegmentLength: 0x0

  InitiatorTaskTag: 0x29000010

  LUN: 0x0

  Target Transfer Tag: 0xffffffff

  CommandSequenceNumber: 0xc6e

  ExpectedStatusSequenceNumber: 0xc8b

(144)19:19:06 DEBUG [main] connection.TargetSenderWorker - connection.getStatusSequenceNumber: 3211

(167)19:19:06 DEBUG [main] connection.TargetSenderWorker - Sending this PDU:

  ParserClass: NOPInParser

  ImmediateFlag: false

  OpCode: 0x20

  FinalFlag: true

  TotalAHSLength: 0x0

  DataSegmentLength: 0x0

  InitiatorTaskTag: 0x29000010

  LUN: 0x0

  Target Transfer Tag: 0xffffffff

  StatusSequenceNumber: 0xc8b

  ExpectedCommandSequenceNumber: 0xc6e

  MaximumCommandSequenceNumber: 0xc6e

(228)19:19:11 DEBUG [main] connection.TargetSenderWorker - Receiving this PDU:

  ParserClass: NOPOutParser

  ImmediateFlag: true

  OpCode: 0x0

  FinalFlag: true

  TotalAHSLength: 0x0

  DataSegmentLength: 0x0

  InitiatorTaskTag: 0x2a000010

  LUN: 0x0

  Target Transfer Tag: 0xffffffff

  CommandSequenceNumber: 0xc6e

  ExpectedStatusSequenceNumber: 0xc8c

....

...

...

...

(228)19:20:02 DEBUG [main] connection.TargetSenderWorker - Receiving this PDU:

  ParserClass: TaskManagementFunctionRequestParser

  ImmediateFlag: true

  OpCode: 0x2

  FinalFlag: true

  TotalAHSLength: 0x0

  DataSegmentLength: 0x0

  InitiatorTaskTag: 0x36000010

  LUN: 0x0

  Referenced Task Tag: 0x6b000010

  CommandSequenceNumber: 0xc6e

  ExpectedStatusSequenceNumber: 0xc98

  RefCmdSN: 0xab6

  ExpDataSN: 0x0

Thanks, Felipe

[Felipe Gutierrez]

I am using async option to export me nfs disk. http://unixhelp.ed.ac.uk/CGI/man-cgi?exports

This help all writes on the disk to be very fast.

[Donald Williams]

Hello Felipe, 

 I'm not sure about anyone else, but I wouldn't expect that tweaking the iSCSI settings you've been talking about will improve this. 

 Have you tested just connecting from server to storage via iSCSI?   Take NFS out of the picture.  iSCSI is very dependent on the network.  What kind of switch are you using?   Is flowcontrol enabled?    Have you configured MPIO?  

 With just iSCSI you can potentially getting better triage data from the iSCSId logs. 

 don 

 

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[Felipe Gutierrez]

Hi Donald, thanks for reply,

I realized the my problem was the NFS. The default mode is sync, now I am exporting my NFS async at /etc/export. It is very dangers because I can corrupt my data, but I am gonna put a firewall to these two machines.

Thanks again!

Felipe

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