Let’s fill all disk, make gaps with free blocks and try to allocate large blocks ranges.
Create 4G filesystem same way as before:
For 4k block group size is 128mb. 31 group for 4G. Let’s create 240 files in every group. Then delete half of them. And try to allocate large file.
#!/bin/bash
OSTCOUNT=1 OSTSIZE=4194304 lustre/tests/llmount.sh
echo “1” > /sys/fs/ldiskfs/loop1/mb_stats
ls -l /mnt/lustre
#128mb group
#create 128 1M files in eatch of group
echo “Creating 110*31 files …”
for group in $(seq 31)
do
_group=$(printf “%02d” $group);
for nfile in $(seq 240)
do
_nfile=$(printf “%03d” $nfile)
dd if=/dev/zero of=/mnt/lustre/foofile-$_group-$_nfile bs=524288 count=1 &> /dev/null
done
done
echo “done”
echo “created files”
ls -l /mnt/lustre | wc -l
echo “Deleting half of files …”
for group in $(seq 31)
do
_group=$(printf “%02d” $group);
for nfile in $(seq 240)
do
_nfile=$(printf “%03d” $nfile)
if [ “$(($nfile % 2))” -eq 0 ]
then
#echo “Deleting $_group $_nfile”
rm -f /mnt/lustre/foofile-$_group-$_nfile
fi
done
done
echo “files after deleting”
ls -l /mnt/lustre | wc -l
df | grep “/mnt/lustre”
dd if=/dev/zero of=/mnt/lustre/foofile bs=1048576 count=2000
lustre/tests/llmountcleanup.sh
Now we get expected result.
[ 5148.016557] LDISKFS-fs (loop1): mballoc: 1376278 blocks 9524 reqs (9007 success)
[ 5148.016560] LDISKFS-fs (loop1): mballoc: 282165 extents scanned, 745 goal hits, 1988 2^N hits, 1389 breaks, 0 lost
[ 5148.016562] LDISKFS-fs (loop1): mballoc: (511, 1405, 0) useless c(0,1,2) loops
[ 5148.016563] LDISKFS-fs (loop1): mballoc: 31 generated and it took 63044
[ 5148.016564] LDISKFS-fs (loop1): mballoc: 1066390 preallocated, 125 discarded
mballoc: (511, 1405, 0) useless c(0,1,2) loops – allocator iterates other block groups and can’t find requested large range.
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