[LU-6545] MPIIO short reads

Related — Thu, 15 Oct 2015 23:06:44 +0000

One of our filesystem is experiencing, what we guess are, short reads that results in NaNs using mpiio function call 'MPI_FILE_READ_AT_ALL'

This can be reproduced every time if the data is read from disk and not cache. So doing a echo 1 > /proc/sys/vm/drop_caches then running the code will error every time, but running the code a second or third time will not produce the error.

NOTE:
This occurs only when the file is striped >1 ost.
In the debug logs the datafile has a fid of [0x2000b2ebc:0x358:0x0]
During the debugging I disabled read ahead

I have captured a full debug trace of lustre on the client and will upload to tftp site.

Whamcloud Community JIRA

[LU-6545] MPIIO short reads