samtool sort: truncated file error?

[shawpa]

I was trying to sort a bam file using samtools. The original bam file is about 34.4GB. After I ran the sorting, the output file was only 12.9GB. If it worked correctly I don't see where over half the data went. I checked a log and it says

[bam_sort_core] truncated file. Continue anyway.
[bam_sort_core] merging from 103 files...

I'm not sure what this means. I think it might be a memory issue and its creating tmp dir where there isn't enough space maybe. I wasn't able to find any posts with this error already.