Proliant DL380 Gen9 - smartarry P840- SW RAID10 vs HW

[fawzi1]

Hi,

For RAID10, does it make a Difference difference whether i use SW (mdadm) or HW (smartArry P840)?

My server has 3 vm 2 File servers and one ownCloud server.

I am thingking for my current usage, and RAID10, the smartarray card may become more of a hassle than a benefit. I find it a hassle since:

1- i don't have control over it from within the OS,

2- As far as i know, i have to always boot to make any change

3- I don't really want to learn yet another tool/HW

4- Finally, though it is extremely rare, if samrtArray breaks down, it is harder to recover from it.

Any thoughts or numbers on this, would be helpful...

thanks,

[Jimmy Vance]

Since you mention mdadm I'll assume you are using Linux. The P840 will run circles around madm as far as rebuilds and the cache module in the P840 will boost file system performance.  mdadm is very slow to rebuild, and is cumbersome to use  (my opinion) 
There are tools for Linux to mange the array , hpssa and hpssascriting. You can add them along with several other tools to manage the server via the OS at the SDR http://downloads.linux.hpe.com . The SDR is a repository that allows you to access HPE software utilities via native OS tools like yum, zypper and apt.

When using the Smart Array, the array information is stored on each drive in the array(s), if a controller failes, replacing the controller is all that is required. 

[fawzi1]

for RAID10, web seraches will show claims that the difference in speed is negligable... that's why i was hoping to get some proffisionally published numbers to back/refute  that claim from this forum.

[fawzi1]

HI jimmy,

First off, thanks for mentioning the linux tools for the smart array controller... i downloaded them and they saved me a ton of time having to reboot every time i want to make a change on my HDDs.

So i listened to you and re-did my system with using the P840ar with one large RAID10.  so no mdadm.

Then i used samba server and tested download from another PC.  sadly,  there is no difference between HW RAID and the SW RAID... well there is a difference of less than 1%.. negligable.

my test was basically opening a large CAD file, which is what this system will be used for. 

can you help me see what i may be doing wrong and not seeing the expected speed of the HW RAID?  is it samba, or is it not visible unless i have huge demand, which i did not have here?

thanks,

[Jimmy Vance]

The network is probably your bottleneck and not the disk controller.  You need to runs some disk tests locally to the system to test disk performance