PowerFlex 3.0: SDS panics when inflight checksum is enabled

Summary: SDS process might crash during regular I/O operations, and process panic is reported in the SDS traces.

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Symptoms

This problem can occur when an SDC sends a zero-write (a write I/O where the data payload is all zeros) to an SDS. The inflight checksum is enabled in the system.

SDS disconnects from an MDM, then reconnect. The "exp.0" file shows the following panic string:

02/03 14:58:34.740139 Panic in file /data/builds/workspace/ScaleIO-Common-Job@2/src/tgt/ioh/ioh.c, line 2227, function ioh_PrepareDataAndChksmForWrite, PID 2648.Panic Expression !(((((*pReqFlags) & (0x8)) != 0) ? ((BOOL)1) : ((BOOL)0))) PANIC_ID_tgt_1497349764087.
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(mosDbg_PanicPrepare+0x135) [0x8dd885]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(ioh_PrepareDataAndChksmForWrite+0x22d) [0x5f938d]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(iohComb_WritePrimary+0x644) [0x5fef84]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(ioh_Write+0x703) [0x601fe3]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(ioh_NewRequest+0x42b5) [0x606995]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(contNet_RecvIORequest+0x28d) [0x609a9d]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(netRecvGroup_WaitForWork+0x38f) [0x6cec7f]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(netRecvGroup_WaitForWorkLoop+0x18) [0x6cee08]
/opt/emc/scaleio/sds/bin/sds-3.0.1000.208(mosUmt_StartFunc+0x7a) [0x717d5a]
/lib64/libc.so.6(+0x48190) [0x7fcb84ece190]

Impact

Depending on the state of the system, it can temporarily go to either DEGRADED or DATA_FAILED state.

Cause

When the inflight checksum is enabled in the system, SDCs calculate and attach a checksum to each write I/O. If a write request happens to be all-zeros, the checksum might not be calculated (invalid) which trigger an SDS panic - it expects a valid checksum for all writes, even an all-zeros write.

Resolution

Disable the inflight checksum mechanism.

Additional Information

Impacted Versions
PowerFlex 3.0.x

Fixed In Version
PowerFlex 3.5 and later

Affected Products

ScaleIO, PowerFlex Software
Article Properties
Article Number: 000185114
Article Type: Solution
Last Modified: 25 Nov 2025
Version:  6
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