The guide talks you through the steps to carry out performance tests on the Hardware & Innovation Bench server.

Different RAID volume compositions

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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
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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.
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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

Disk performance tests

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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
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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

Changing RAID

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.
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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.