why sorted.bam file size is increased after using fixmate in picard

Question

[rj.rezwan]

Hi, I have fixmate the abc.sorted.bam (12G) file using picard tool. But my output fixmate.bam file is increased to 13G. it this fine or I should need to worry about it? My command is here:

picard FixMateInformation I=abc_sorted.bam O=fixmate_abc.bam VALIDATION_STRINGENCY=STRICT CREATE_INDEX=TRUE

[Pierre Lindenbaum]

try again with

 COMPRESSION_LEVEL=9