UNIX BLOG

Introduction:

How to install raid10 with 4 or more drives with hetzner with faster disk layout -f2

I tested raid10 with 3 layouts(n2, f2, and o2) , HDD SEAGATE  drives are 3TB with around 180MB/s speed.

Every new Seagete hetzner Drive drive have 3 plates , Model ST3000DM001

Test with one HDD hdparm -t /dev/sda1

Timing buffered disk reads: 512 MB in  2.77 seconds = 184.98 MB/sec

Test raid 10 f2 configuration

hdparm -t /dev/md1

/dev/md1:
Timing buffered disk reads: 1558 MB in  3.01 seconds = 516.92 MB/sec

It’s a very good result especially considering software reaid.

Please note that on Linux kernel 3.2 mdadm works much faster then 2.6.32 standart debian squueze kernel wich gives us around 380 – 420MB/S

Instructions:

Boot with rescue CD in standart hetzner tools

 

 

 

 

 

 

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Login to the SSH console of the servers, and type the following commands:

mkdir /home/images
mkdir /home/install
cp –dpR /root/.oldroot/install/ /home/install/

Now copy the selected image
For Debian Squeeze:

cp /root/.oldroot/nfs/images/Debian-60-squeeze-64-minimal.tar.gz 
/home/images/

FOr CentOS 6.3 :

cp /root/.oldroot/nfs/images/CentOS-63-64-minimal.tar.gz /home/images/

edit /home/install/functions.sh yes | mdadm -q -C $raid_device -l$SWRAIDLEVEL -p f2 -n4
-p f2

– points to the fastest raid10 performance of raid10
/home/install/installimage to lounch the setup

Choose raid10 as software raid in config file
That’s all.
Now check if all is ok:
Should be something like that:

cat /proc/mdstat
Personalities : [raid1] [raid10] [raid0] [raid6] [raid5] [raid4]
md2 : active raid10 sdd3[3] sdc3[2] sdb3[1] sda3[0]
5851088896 blocks super 1.2 512K chunks 2 far-copies [4/4] [UUUU]
[>....................] resync = 0.9% (54960832/5851088896) 
finish=534.8min speed=180612K/sec

Please note that for SWAP and boot partition, it’s better to leave RAID1 , as /boot partition will not boot with raid10 on grub and lilo.
SWAP partition for secureness also is good to be raid 1 with 4 drives partition.
Personally I like to give to / (Root partition) around 30GB and 4 drives of raid1, I would like to have access to my main partition if a raid10 drive will fail.
Hetzner use very fast drives Seagate Baracuda newest generation.
It can give up to 180 – 200MB/s performance per one drive.
If got maximum of 600MB/s with raid10 performance of sequential read.

Thank you for attention, hope you ejoyed the article.

Tags: hetzner, image, mdadm, raid10, rescue, software raid