freenas with bios raid

[ngotuanan1010]

Hello everyone,
Firstly, I am a newbie in FreeNas and sorry for my bad English.
I have tried to configure my server as a shared storage for VMWare servers using FreeNas solution. Here is my FreeNas server specs:
Dell R710
1 x Intel(R) Xeon(R) CPU E5504 @ 2.00GHz
Memory 8161MB
Raid Controller: Dell PERC H700
HDD: 2x 146 SAS 15K, 4 x 1TB SATA 7200

I created 2 raid arrays: Raid 1 for 2 x 146 SAS 15K (Array1) and Raid 5 for 4 x 1TB SATA 7200 (Array2)
FreeNAS 9.2 was installed on Array1 and on WebGUI, I could see Array2 as A drive.
I created a ZFS volume, compression = off and shared with NFS.

Inside FreeNas server, I try to use "dd" command for testing performance and I found that the write speed is only from 10 - 12 MB/s at the first time using. After referring some suggestions on some forums, I tried to change some thing related sysctl (http://www.mamisano.com/2009/10/28/freenas-tuning-for-better-performance/) and the write speed is increased to around 30 MB/s

I though it is not expected speed and the problem because of software raid and I had a plan to use RaidZ1. So, I deleted ZFS volume, deleted Array2 and I had 4 none-raid disks. However, after rebooting, I logged in WebGUI and none of hard disks can detected so I could not do anything.

Please give me some advice in my case. Is 30MB/s max speed I can get with SATA 7200 disks?
Look forward to hearing from all of you.
Best Regards,
Ngo An

 

[HoneyBadger]

Hello Ngo,

FreeNAS is not designed to use RAID arrays - it expects to have a raw, unmanaged disk. Your Dell PERC H700 controller is blocking it from being able to work as expected, because it only allows the creation of arrays rather than passing the disks through. This is why the disks are not visible after deleting Array 2.

The sysctl tuning there is not recommended and it also applies to FreeNAS 7.x as opposed to the 9.2 version you installed recently.

I would suggest that you do the following:

1. Connect the 4x1TB SATA drives to the SATA ports on your Dell R710 motherboard (if you can get at them) - if not, then purchase a Dell PERC H200 which does allow drive passthrough and will be fully compatible with your R710's storage slot. Most "RAID controllers" are not compatible with FreeNAS for the reasons you are seeing with your PERC H700.

2. Obtain a USB drive (4GB or larger) and reinstall a fresh copy of FreeNAS directly on this USB drive. FreeNAS does not require or use the drive after boot except to save configuration, so you will not get increased performance from using the 15K SAS drives.

3. Don't perform any sysctl tuning. Because of the variety of guides and versions out there it may do more harm than good.

With regard to use as a VMware datastore you will want to configure the four disks in a stripe of mirrors (similar to RAID10) and because of only 8GB of RAM you will not get a high level of performance.

 

[ngotuanan1010]

Hello HoneyBadger,
Sorry for my late response and many thanks for your very quick and adequate answer.
Unfortunately, I have only PERC SAS 6/ir for this project right now and is it compatibility with passing the disks through in FreeNAS?
And, Could you help me figure out the best practice for my actual hardware?
Thank you very much,
Ngo An.

 

[Dave Crenshaw]

ngotuanan1010: you can probably get by with a IBM M1015 (you will need to cross flash it) SAS card in one of the PCI slots and use a SAS cable to the SAS expander at the drive bays. I cant remember which cable the SAS 6/ir uses at the expander but it is a cheap option and a very good performing card.

 

[HoneyBadger]

Hello again!

I believe the SAS 6/iR can be crossflashed with the LSI SAS3081E-R to enable true passthrough, but I've never done the process myself and others have reported some difficulty in it. I would second the suggestion of the IBM M1015 above.

If neither is an option than you could create a single RAID0 array out of each individual drive (so you would have six arrays, each containing a single drive) and configure them within ZFS. This is not optimal though.