[LU-17182] lctl pool_add is slow when using individual OST

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Severity: 3
• Assignee: Feng Lei
• Reporter: Raphael Druon

Description

Using lctl pool_add FS OST0 OST1... is way slower than using an hostlist expression like OST[0-7], see an example below:

[root@localhost ~]# time lctl pool_add fs.pool_test fs-OST[0-7]
OST fs-OST0000_UUID added to pool fs.pool_test
OST fs-OST0001_UUID added to pool fs.pool_test
OST fs-OST0002_UUID added to pool fs.pool_test
OST fs-OST0003_UUID added to pool fs.pool_test
OST fs-OST0004_UUID added to pool fs.pool_test
OST fs-OST0005_UUID added to pool fs.pool_test
OST fs-OST0006_UUID added to pool fs.pool_test
OST fs-OST0007_UUID added to pool fs.pool_test

real    0m9.008s
user    0m0.000s
sys     0m0.007s
[root@localhost ~]# time lctl pool_add fs.pool_test OST0000 OST0001 OST0002 OST0003 OST0004 OST0005 OST0006 OST0007
OST fs-OST0000_UUID added to pool fs.pool_test
OST fs-OST0001_UUID added to pool fs.pool_test
OST fs-OST0002_UUID added to pool fs.pool_test
OST fs-OST0003_UUID added to pool fs.pool_test
OST fs-OST0004_UUID added to pool fs.pool_test
OST fs-OST0005_UUID added to pool fs.pool_test
OST fs-OST0006_UUID added to pool fs.pool_test
OST fs-OST0007_UUID added to pool fs.pool_test

real    1m7.024s
user    0m0.004s
sys     0m0.014s

One could expect that both command to have the same runtime