OVH Guide

Hardware & Innovation Bench

How to carry out performance tests on the Hardware & Innovation Bench server.

  • Hardware & Innovation Bench
  • HG
  • performance

Different types of RAID are split between the server and two DAS systems. You can therefore test RAID hardware with an LSI MegaRAID 9271-4i card, but you can also test RAID software, and hardware with different types of disk.

RAID hardware with an LSI MegaRAID 9271-4i card

Devices Composition of hardRAID Type
/dev/sda 2 x 120 GB SSD DC S3500 disks (OS pre-installed) RAID 1
/dev/sdb 2 x 240 GB SSD DC S3500 disks RAID 1
/dev/sdc 2 x 600 GB SSD DC S3500 disks RAID 1
/dev/sdd 2 x SAS 15K rpm HGST disks RAID 1
/dev/sde 2 x 900Go SAS 10K rpm HGST disks RAID 1
/dev/sdf 2 x 4 TB SAS 7200 rpm HGST disks RAID 1

System:

The system is installed on the /dev/sda device

RAID hardware with an LSI Megaraid 9271-4i card with CacheCade and FastPath

Devices Composition of RAID Type
/dev/sdg 2 x 240 GB SSD DC S3500 disks RAID 1 FastPath
/dev/sdh 2 x 600 GB SSD DC S3500 disks RAID 1 FastPath
/dev/sdi 2 x 600 GB SAS 15K rpm HGST disks RAID 1 CacheCade
/dev/sdj 2 x 900 GB SAS 10K rpm HGST disks RAID 1 CacheCade
/dev/sdk 2 x 4 TB SAS 7200 rpm HGST disks RAID 1 CacheCade

CacheCade disk:

For CacheCade: 1 x 480 GB SSD DC S3500 disk is configured.

RAID software

Devices Composition of RAID type
/dev/md1 2 x 240 GB SSD DC S3500 disks (/dev/sdl1, /dev/sdm1) RAID 1
/dev/md2 2 x 600 GB SSD DC S3500 disks (/dev/sdn1 & /dev/sdo1) RAID 1
/dev/md3 2 x 600 GB SAS disks (/dev/sdp1 & /dev/sdq1) RAID 1
/dev/md4 2 x 900 GB SAS 10K rpm HGST disks (/dev/sdr1 & /dev/sds1) RAID 1
/dev/md5 2 x 4 TB SAS 7200 rpm HGST disks (/dev/sdt1, /dev/sdu1)) RAID 1

To test different performances of different RAID types:

Read test

The hdparm command allows you to measure the disk's read level:

hdparm -Tt /dev/DEVICE

DEVICE is the device to test.

Example: (device to test/dev/sda)

hdparm -Tt /dev/sda

/dev/sda:
Timing cached reads: 24358 MB in 2.00 seconds = 12191.84 MB/sec
Timing buffered disk reads: 844 MB in 3.00 seconds = 281.19 MB/sec

Write test

The dd command allows you to measure the disk's write level:

dd if=/dev/zero of=/DOSSIER/test.data bs=8k count=128k

FOLDER is the folder where the hardware partition to test has mounted to.

Example: (partition /dev/sda2 mounted to /home)

dd if=/dev/zero of=/home/test.data bs=8k count=128k
131072+0 records in
131072+0 records out
1073741824 bytes (1.1 GB) copied, 0.702882 s, 1.5 GB/s

All RAIDs come in RAID 1 by default. You can choose to upgrade them to RAID 2.

Deleting RAID

All existing data will be deleted when you delete RAID.

Changing RAID software

To change the RAID, you will firstly need to delete it. Then:

  • Retrieve the RAID information:
mdadm --detail /dev/mdX

Example:

mdadm --detail /dev/md1
/dev/md1:
Version: 1.2
Creation Time: Fri Jul 4 21:14:12 2014
Raid Level: raid1
Array Size: 234298176 (223.44 GiB 239.92 GB)
Used Dev Size: 234298176 (223.44 GiB 239.92 GB)
Raid Devices: 2
Total Devices: 2
Persistence: Superblock is persistent

Update Time: Fri Jul 11 13:05:01 2014
State: clean
Active Devices: 2
Working Devices: 2
Failed Devices: 0
Spare Devices: 0

Name: ns6427926.ip-5-135-134.eu:1 (local to host ns6427926.ip-5-135-134.eu)
UUID: 299015e1:50b4554c:faf58dbc:74d3c2a4
Events: 20

Number Major Minor RaidDevice State
0 8 177 0 active sync /dev/sdl1
1 8 193 1 active sync /dev/sdm1
  • You must change the status of each of these partitions to "fail" before removing them from the RAID software:
mdadm --manage /dev/md0 --fail /dev/sdX

Example:

mdadm --manage /dev/md1 --fail /dev/sdl1
mdadm --manage /dev/md1 --fail /dev/sdm1
  • Stop the RAID
mdadm --manage --stop /dev/mdX[/code

[u]Example:[/u]

[code]mdadm --manage --stop /dev/md1
  • Remove the superblock:
mdadm --zero-superblock /dev/sdX

Example:

mdadm --zero-superblock /dev/sdl1
mdadm --zero-superblock /dev/sdm1
  • Set up the RAID:
mdadm --create /dev/mdZ --level=L --assume-clean --raid-devices=N /dev/sdX1 /dev/sdY1

/dev/mdZ: the RAID volume that you're going to set up (it must not/no longer be present). --level=: the RAID type (0,1). --raid-devices=: the number of devices in the RAID system. /dev/sdX1 /dev/sdY1: the partition(s) in software RAID.

Example: (/dev/md1 in RAID 0 with /dev/sdl1 and /dev/sdm1 partitions)

mdadm --create /dev/md1 --level=0 --assume-clean --raid-devices=2 /dev/sdl1 /dev/sdm1

Don't forget to format the /dev/mdX partition and mount it before you perform write tests.