Hi,
Now I report the result of dm-band bandwidth control test I did yesterday.
I've got really good results that dm-band works as I expected. I made
several band-groups on several disk partitions and gave them heavy I/O loads.
Hardware Spec.
==============
DELL Dimention E521:
Linux kappa.local.valinux.co.jp 2.6.23.14 #1 SMP
Thu Jan 24 17:24:59 JST 2008 i686 athlon i386 GNU/Linux
Detected 2004.217 MHz processor.
CPU0: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ stepping 02
Memory: 966240k/981888k available (2102k kernel code, 14932k reserved,
890k data, 216k init, 64384k highmem)
scsi 2:0:0:0: Direct-Access ATA ST3250620AS 3.AA PQ: 0 ANSI: 5
sd 2:0:0:0: [sdb] 488397168 512-byte hardware sectors (250059 MB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 2:0:0:0: [sdb] Write cache: enabled, read cache: enabled,
doesn't support DPO or FUA
sdb: sdb1 sdb2 < sdb5 sdb6 sdb7 sdb8 sdb9 sdb10 sdb11 sdb12 sdb13 sdb14
sdb15 >
The results of bandwidth control test on partitions
===================================================
The configurations of the test #1:
o Prepare three partitions sdb5, sdb6 and sdb7.
o Give weights of 40, 20 and 10 to sdb5, sdb6 and sdb7 respectively.
o Run 128 processes issuing random read/write direct I/O with 4KB data
on each device at the same time.
o Count up the number of I/Os and sectors which have done in 60 seconds.
The result of the test #1
---------------------------------------------------------------------------
| device | sdb5 | sdb6 | sdb7 |
| weight | 40 (57.0%) | 20 (29.0%) | 10 (14.0%) |
|-----------------+-------------------+-------------------+-----------------|
| I/Os (r/w) | 6640( 3272/ 3368)| 3434( 1719/ 1715)| 1689( 857/ 832)|
| sectors (r/w) | 53120(26176/26944)| 27472(13752/13720)| 13512(6856/6656)|
| ratio to total | 56.4% | 29.2% | 14.4% |
---------------------------------------------------------------------------
The configurations of the test #2:
o The configurations are the same as the test #1 except this test doesn't
run any processes issuing I/Os on sdb6.
The result of the test #2
---------------------------------------------------------------------------
| device | sdb5 | sdb6 | sdb7 |
| weight | 40 (57.0%) | 20 (29.0%) | 10 (14.0%) |
|-----------------+-------------------+-------------------+-----------------|
| I/Os (r/w) | 9566(4815/ 4751)| 0( 0/ 0)| 2370(1198/1172)|
| sectors (r/w) | 76528(38520/38008)| 0( 0/ 0)| 18960(9584/9376)|
| ratio to total | 76.8% | 0.0% | 23.2% |
---------------------------------------------------------------------------
The results of bandwidth control test on band-groups.
=====================================================
The configurations of the test #3:
o Prepare three partitions sdb5 and sdb6.
o Create two extra band-groups on sdb5, the first is of user1 and the
second is of user2.
o Give weights of 40, 20, 10 and 10 to the user1 band-group, the user2
band-group, the default group of sdb5 and sdb6 respectively.
o Run 128 processes issuing random read/write direct I/O with 4KB data
on each device at the same time.
o Count up the number of I/Os and sectors which have done in 60 seconds.
The result of the test #3
---------------------------------------------------------------------------
|dev| sdb5 | sdb6 |
|---+------------------------------------------------------+----------------|
|usr| user1 | user2 | other users | all users |
|wgt| 40 (50.0%) | 20 (25.0%) | 10 (12.5%) | 10 (12.5%) |
|---+------------------+------------------+----------------+----------------|
|I/O| 5951( 2940/ 3011)| 3068( 1574/ 1494)| 1663( 828/ 835)| 1663( 810/ 853)|
|sec|47608(23520/24088)|24544(12592/11952)|13304(6624/6680)|13304(6480/6824)|
| % | 48.2% | 24.9% | 13.5% | 13.5% |
---------------------------------------------------------------------------
The configurations of the test #4:
o The configurations are the same as the test #3 except this test doesn't
run any processes issuing I/Os on the user2 band-group.
The result of the test #4
---------------------------------------------------------------------------
|dev| sdb5 | sdb6 |
|---+------------------------------------------------------+----------------|
|usr| user1 | user2 | other users | all users |
|wgt| 40 (50.0%) | 20 (25.0%) | 10 (12.5%) | 10 (12.5%) |
|---+------------------+------------------+----------------+----------------|
|I/O| 8002( 3963/ 4039)| 0( 0/ 0)| 2056(1021/1035)| 2008( 998/1010)|
|sec|64016(31704/32312)| 0( 0/ 0)|16448(8168/8280)|16064(7984/8080)|
| % | 66.3% | 0.0% | 17.0% | 16.6% |
---------------------------------------------------------------------------
Conclusions and future works
============================
Dm-band works well with random I/Os. I have a plan on running some tests
using various real applications such as databases or file servers.
If you have any other good idea to test dm-band, please let me know.
Thank you,
Ryo Tsuruta.
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