- The metadata server stores names, permissions, and locations. The
data servers store bytes.
- A thousand small files mean a thousand metadata operations. One
archive means one.
- Home is for the small source file. A 10 GB working file is scratch.
A result you must keep is project space.
- Snellius home is 200 GiB, backed up, with three weeks of deleted
files in the backup.
- Scratch-shared lasts about 14 days. Scratch-local lasts about 6
days. Scratch-node ends with the job.
- Project space and the archive last until the project ends. The
archive is the slow, backed-up copy.
- The course cluster tab replaces this list. Do not invent
/scratch-shared there.
-
myquota is the Snellius report. df -h and
du -sh are the tools when it is absent.
-
pwd prints the current directory. A new shell starts in
home.
-
mkdir -p /scratch-shared/$USER is the Snellius scratch
directory. The course cluster uses the path in the tab.
-
ls of an empty directory prints nothing.
- After
mv, ls shows the new name only.
cp leaves the original.
-
rmdir removes an empty directory. On a non-empty
directory it errors, and it succeeds after you empty it.
- The mode string is type, then owner, group, and everyone else.
-
chmod 640 sets -rw-r-----.
chmod g-r then sets -rw-------.
- Snellius home is 200 GiB.
myquota prints the cap and
the inode cap.
- Without
myquota, df -h shows the mounts
and du -sh ~ shows home.
-
$TMPDIR in a job is that job’s directory. Two jobs on
tcn386 got scur1448.4401218 and
scur1448.4401219.
-
realpath on those jobs printed
/gpfs/scratch1/nodespecific/tcn386/ plus the same job
directory.
- Scratch-node is
--constraint=scratch-node on Snellius.
The course cluster drops the constraint and uses
$TMPDIR.
-
sbatch run.sh writes 10^6 through 10^9 values. A small
cluster uses iend=8 wdir=TMPDIR sbatch run.sh.
- A thousand small files copy slower than one archive of the same
bytes. Clean the test up.
