tomevault-io Lustre Scratch Troubleshooting
Overview
Diagnose "disk full" errors on Lustre scratch when overall free space exists. Identify quota, OST/MDT, or striping issues and redirect writes to a healthy pool.
Quick triage
Check global space, inodes, and quotas:
df -h /global/scratch
df -i /global/scratch
lfs quota -u $USER /global/scratch
lfs quota -g $(id -gn) /global/scratch
Inspect OST/MDT usage:
lfs df -h /global/scratch
lfs df -i /global/scratch
NOTE: If specific OSTs are 100% while filesystem_summary has space, writes can fail depending on striping.
Diagnose striping and pools
Check where the failing path is striped:
lfs getstripe -d /global/scratch/users/$USER/workspace/tmp
lfs getstripe /path/to/failing/file
List available pools (cluster-specific names vary):
lfs pool_list /global/scratch
lfs pool_list lr6.ddn_hdd
lfs pool_list lr6.ddn_nvme2
Redirect TMPDIR to a healthy pool
Create a temp directory with explicit striping that avoids full OSTs:
mkdir -p /global/scratch/users/$USER/workspace/tmp_hdd
lfs setstripe -p ddn_hdd -c 1 -S 1M /global/scratch/users/$USER/workspace/tmp_hdd
lfs getstripe -d /global/scratch/users/$USER/workspace/tmp_hdd
Use it for a single command:
TMPDIR=/global/scratch/users/$USER/workspace/tmp_hdd <command>
If available, use the helper script in this repo:
bin/reset_lustre_tmp.sh --pool ddn_hdd
Optionally swap the shared temp path to a symlink (only after verifying it is safe to move):
ls -la /global/scratch/users/$USER/workspace/tmp
backup="/global/scratch/users/$USER/workspace/tmp_old_$(date +%Y%m%d_%H%M%S)"
mv /global/scratch/users/$USER/workspace/tmp "$backup"
ln -s /global/scratch/users/$USER/workspace/tmp_hdd /global/scratch/users/$USER/workspace/tmp
NOTE: Pool names and OST IDs vary by cluster. Prefer pools with ample free space and avoid pools tied to full OSTs.
Validate
Confirm write access and rerun the failing command:
touch $TMPDIR/._lustre_write_test
rm -f $TMPDIR/._lustre_write_test
If errors persist, recheck striping on the specific path and consult cluster admins for OST health.
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