[LU-3782] Divizion by zero in ost-pools 18

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.9.0
• Labels: patch
• Environment: 4-nodes virtual cluster, 2 OST 700MB per each.
• Severity: 3
• Assignee: WC Triage
• Reporter: Alexander Lezhoev

Description

ost-pools: create_perf () does not check if files were actually created on each iteration:

create_perf() {
...

    stat=$(createmany -o $cdir/${tfile} -$numsec | tail -1)
    files=$(echo $stat | cut -f 2 -d ' ')
    echo $stat 1>&2
..
}

$numsec is fixed as 15 seconds.
So test failed if there is lack of inodes and no files have been created:

== ost-pools test 18: File create in a directory which references a deleted pool == 15:47:58 (1371152878)
Create performance, iteration 1, 15 seconds x 3
total: 40940 creates in 14.28 seconds: 2867.34 creates/second
iter 1: 40940 creates without pool
mft51: Pool lustre.testpool created
mft51: OST lustre-OST0000_UUID added to pool lustre.testpool
mft51: OST lustre-OST0001_UUID added to pool lustre.testpool
total: 38563 creates in 14.42 seconds: 2674.14 creates/second
iter 1: 38563 creates with pool
mft51: OST lustre-OST0000_UUID removed from pool lustre.testpool
mft51: OST lustre-OST0001_UUID removed from pool lustre.testpool
mft51: Pool lustre.testpool destroyed
total: 43721 creates in 13.57 seconds: 3221.95 creates/second
iter 1: 43721 creates with missing pool

Create performance, iteration 2, 15 seconds x 3
total: 0 creates in 0.00 seconds: 0.00 creates/second
iter 2: 0 creates without pool
mft51: Pool lustre.testpool created
mft51: OST lustre-OST0000_UUID added to pool lustre.testpool
mft51: OST lustre-OST0001_UUID added to pool lustre.testpool
total: 0 creates in 0.00 seconds: 0.00 creates/second
iter 2: 0 creates with pool
mft51: OST lustre-OST0000_UUID removed from pool lustre.testpool
mft51: OST lustre-OST0001_UUID removed from pool lustre.testpool
mft51: Pool lustre.testpool destroyed
total: 0 creates in 0.00 seconds: 0.00 creates/second
iter 2: 0 creates with missing pool

Create performance, iteration 3, 15 seconds x 3
total: 0 creates in 0.00 seconds: 0.00 creates/second
iter 3: 0 creates without pool
mft51: Pool lustre.testpool created
mft51: OST lustre-OST0000_UUID added to pool lustre.testpool
mft51: OST lustre-OST0001_UUID added to pool lustre.testpool
total: 0 creates in 0.00 seconds: 0.00 creates/second
iter 3: 0 creates with pool
mft51: OST lustre-OST0000_UUID removed from pool lustre.testpool
mft51: OST lustre-OST0001_UUID removed from pool lustre.testpool
mft51: Pool lustre.testpool destroyed
total: 0 creates in 0.00 seconds: 0.00 creates/second
iter 3: 0 creates with missing pool

Avg files created in 15 seconds without pool: 0
Avg files created in 15 seconds with pool: 0
Avg files created in 15 seconds missing pool: 0
/usr/lib64/lustre/tests/ost-pools.sh: line 1000: (0 - 0) * 100 / 0: division by 0 (error token is "0")
test_18 returned 1

• createmany return code must be checked.
• Number of files should be calculated more flexible.