A fix is available
APAR status
Closed as program error.
Error description
On the client: The first instance of DMA_ERR revolves around a failed attempt at sending an I/O request to the VIOS: 492 h_call: start H_PUT_TCE iar=3F85CFC p1=1000000C p2=2F8000 p3=14742FA001 492 h_call: start H_XIRR iar=3F64F88 p1=19ECD50 p2=1D55526F0C7800 p3=0000 492 h_call: end H_XIRR iar=3F64F88 rc=0000 492 h_call: end H_PUT_TCE iar=3F85CFC rc=0000 492 h_call: start H_PUT_TCE iar=3F85CFC p1=1000000C p2=2F9000 p3=14742FB001 492 h_call: end H_PUT_TCE iar=3F85CFC rc=0000 492 h_call: start H_SEND_CRQ iar=3F9E25C p1=84C099 p2=1D55526F0C85A4 p3=0000 492 h_call: end H_SEND_CRQ iar=FFFFFFFFFFFFFFF4 rc=3F9E25C 492 h_call: start H_PUT_TCE iar=3F80AA8 p1=1000000C p2=2F8000 p3=100C120000340000 492 h_call: end H_PUT_TCE iar=3F80AA8 rc=0000 492 h_call: start H_PUT_TCE iar=3F80AA8 p1=1000000C p2=2F9000 p3=100C120000340000 492 h_call: end H_PUT_TCE iar=3F80AA8 rc=0000 1D1 ERRLG errput: error id=00000000C8BAC8C9 The attempt at H_SEND_CRQ failed with H_DROPPED. From code inspection of vfc_issue(), if H_SEND_CRQ fails with H_DROPPED, we should unmap dma resources, and return the request to the head of the pending queue for a retry.
Local fix
Problem summary
When the Virtual Fibre Channel adapter attribute num_cmd_elems is increased from its default 200 to something like 512 or higher, then under heady IO load, a lot of H_DROPPED errors can be seen against H_SEND_CRQ PHYP calls in traces. There could also be IO errors.
Problem conclusion
VFC Client driver code modified to have proper flow control so that it does not overrun the Server receive queue. This will prevent the H_DROPPED errors coming up repeatedly.
Temporary fix
Comments
APAR Information
APAR number
IV15028
Reported component name
AIX 610 STD EDI
Reported component ID
5765G6200
Reported release
610
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Submitted date
2012-02-06
Closed date
2012-02-06
Last modified date
2013-04-09
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
AIX 610 STD EDI
Fixed component ID
5765G6200
Applicable component levels
R610 PSY U839521
UP12/05/11 I 1000
PTF to Fileset Mapping
U839521 devices.vdevice.IBM.vfc-client.rte 6.1.7.15
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Document Information
Modified date:
09 April 2013