Moving from dedicated. openVZ, KVM or stick with dedicated?

[luispt]

Hello,
root@localhost [/tmp]# dd if=/dev/zero of=/home/10G bs=1M count=10240; sync
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 402.445 seconds, 26.7 MB/s

very slow, no?

In a xen vm i have:

root@localhost [~]# dd if=/dev/zero of=/home/10G bs=1M count=10240; sync
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB) copied, 140 seconds, 76.7 MB/s

Is normal the difference?

Its a RAID 10 system with 4x 1TB SATA drives.

thanks

 

[yatesco]

Maky sure you do:

time 'dd if=/dev/zero of=/home/10G bs=1M count=10240; sync'

Also, you need a minimum of 4 drives to do RAID10....

 

[luispt]

Hello,

I have 4x 1TB in raid 10 and adaptec 5405

root@web [~]# time 'dd if=/dev/zero of=/home/10G bs=1M count=10240; sync'
-bash: dd if=/dev/zero of=/home/10G bs=1M count=10240; sync: No such file or directory

real 0m0.001s
user 0m0.000s
sys 0m0.001s

Whats the error?

 

[bohansen]

You can use this one in stead:

dd if=/dev/zero of=/home/10G bs=1M count=10240 oflag=direct

Also if you have problems with caching you can limit the amount of RAM Linux has access to so you don't have to write extremely big files.
You can do that by adding e.g.: mem=1G to the kernel parameters in /boot/grub/menu.lst.