Re: [SPDK] analyzing spdk error messages

[Daniel Verkamp <daniel.verkamp at intel.com>]

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On 10/12/2016 09:40 AM, Walker, Benjamin wrote:
> On Fri, 2016-10-07 at 17:37 +0000, txcy uio wrote:
>> Hello
>>
>>
>> What is the correct way of analyzing spdk error message (as below which was
>> encountered against a spdk writev cmd) to quickly know what went wrong?
>
> These messages are dumping compact notes about the command that was sent and the
> completion returned. The values are pulled directly from the specification - see
> section 4.6 of NVMe 1.2.1 (http://www.nvmexpress.org/wp-content/uploads/NVM_Expr
> ess_1_2_1_Gold_20160603.pdf) for a full description.
>>
>>
>> WRITE sqid:2 cid:125 nsid:1 lba:4194304 len:16
>
> WRITE - Command Type
> sqid - Submission Queue Id (2)
> cid - Command Id (125). This
> is an arbitrary number we picked for this command. We match completions to
> commands by this number.
> nsid - Namespace Id (1)
> lba - Logical Block Address
> (4194304)
> len - Number of logical blocks (16)
>
>> WRITE FAULTS (02/80) sqid:2 cid:125 cdw0:0 sqhd:002a p:1 m:1 dnr:0
>
> WRITE FAULTS - The error encountered. The (02/80) is (Status Code Type, Status
> Code Value). 02 means media error type, and 80 in the media error category means
> write fault. These values are in hex.
> sqid - Submission Queue Id (2)
> cid - Command
> Id (125). Note how it matches up to the command sent.
> cdw0 - Command DWORD 0 (0).
> Dumped as hex.
> sqhd - Submission Queue Head (2a). The current location of the
> device's submission queue head index.
> p - Phase bit (1)
> m - More (1). If set to 1,
> there is additional error information available that can be obtained by sending
> a Get Log Page command.
> dnr - Do Not Retry (0).
>
> This error seems to indicate that there was a write failure in the media on your device.

Write Fault could also indicate that you passed an incorrect memory 
address and the DMA transfer failed.

Note that the NVMe writev callback requires a physical address, not a 
virtual address.