SB37: Out of space

What it means

A disk data set gets its space in pieces called extents. The first piece is the primary amount from the SPACE parameter. When it fills, the system adds the secondary amount as a new extent, again and again as needed. There are limits. A basic sequential data set or a PDS can have at most 16 extents on one volume, and an extended format data set or a PDSE up to 123. A sequential data set that isn't large format also can't use more than 65,535 tracks on one volume.

SB37 means the data set needed another extent and couldn't get one. The volume had no free space left, the data set had reached one of those limits, or the VTOC had no room to record a new extent. The data set also had no further volume to move to, so the system ended the step with B37.

Message IEC030I carries a reason code after the B37.

• 04 is the one you'll nearly always see, and it covers every case above.
• 08 is rare. The system had to convert the VTOC on the volume to find space, and the conversion failed. That is a job for your storage administrator.
• 0C is rare too. It means too many data sets were already open on the device.

Common causes

• The data grew. A month-end run writes far more than SPACE was sized for.
• SPACE was too small from the start, for example values copied from a test job.
• The secondary amount is small, so the data set uses up its 16 extents before it gets the space it needs. SPACE=(TRK,(5,5)) can never grow past 80 tracks on one volume.
• The volume was nearly full when the job ran, so there was no free space for the next extent.
• The job appends with DISP=MOD every run, and the data set has finally filled.

How to find the problem

1. Read IEC030I. It gives the reason code, the job, step and DD name, the volume serial and the data set name.
2. Check the SPACE parameter on that DD against how much the step wrote. Compare the output record count with a normal run, and suspect a loop if it's far higher.
3. In ISPF option 3.4, enter I next to the data set to see its allocated and used space, its secondary amount and how many extents it has. If it shows 16 extents on one volume, it hit the extent limit.

How to fix it

• Ask for more space, in cylinders for big files, for example SPACE=(CYL,(50,25),RLSE). RLSE gives back unused space when the data set is closed.
• Let the data set use more volumes. VOL=(,,,3) sets a volume count of 3. On SMS-managed storage the data class can do this, so ask your storage team.
• For very large data sets, DSNTYPE=LARGE removes the 65,535-track limit per volume, and extended format, set up by your storage team, raises the extent limit to 123.
• Before you rerun, delete the partly written data set, or make sure the step creates it fresh. Then restart from the failed step.

What it looks like

IEC030I B37-04,IFG0554A,PAYRUN01,STEP030,RPTOUT,0A82,WRK017,PROD.PAYROLL.REPORT
IEA995I SYMPTOM DUMP OUTPUT
  SYSTEM COMPLETION CODE=B37  REASON CODE=00000004
IEF450I PAYRUN01 STEP030 - ABEND=SB37 U0000 REASON=00000004

Last reviewed 2026-10-12 by the WND Software team. Written in our own words. For the full reference, check IBM’s documentation for your z/OS, CICS or Db2 release.