Dell R710 with PERC H310. GPT issues and hardware raid or ZFS?

[Steven Hartland]

----- Original Message ----- 
From: "John" <freebsd at growveg.net>
To: <freebsd-fs at freebsd.org>
Sent: Saturday, June 22, 2013 3:30 PM
Subject: Dell R710 with PERC H310. GPT issues and hardware raid or ZFS?


> Hello list,
> 
> I have a Dell R710 with PERC H310 using hardware raid5 with 4x3TB disks.
> I tried installing FreeBSD-10 and it defaulted to a GPT partitioning
> scheme. FreeBSD installed OK but, on reboot, it couldn't find the
> kernel. I grabbed freebsd-9.1 and it offered me the choice of
> partitioning schemes.
> 
> I had to change the partitioning scheme to "BSD partition" I think it's
> called, in order to get a bootable install. The problem with this is
> that this particular schema can only see about 1TB of space yet there's
> about 10TB there.
> 
> Currently, writes are cached on the hardware raid. (Need to tune it up
> because I left all settings at their default in the configuration
> utility. If it does a lot of writes, it will stall as the buffer fills.)
> 
> I'm happy to let freebsd have this 1TB to itself if I can somehow get it
> to seethe other 9TB. The purpose of the server is to run virtual boxes.
> 
> Hard drive array is seen like this:
> 
> mfi0: <Drake Skinny> port 0xfc00-0xfcff mem
> 0xddffc000-0xddffffff,0xddf80000-0xddfbffff irq 42 at device 0.0 on pci2
> mfi0: Using MSI
> mfi0: Megaraid SAS driver Ver 4.23
> 
> My questions are:
> 
> 0. which is better? ZFS or hardware raid+UFS2?

IMO ZFS. It gives you end to end checksuming, which has saved us more than
once, self healing (no need to do a full array level scrub.

> 1. should I use ZFS on top of the raid5? Guessing not.

You can but I wouldn't advise it, much better to let ZFS have the raw disks.

> 2. should I blat the system and change the raid so it's a JBOD, then
> make it do zfs?

IMO yes.
 
> 3. what other methods can I use to make the existing install see
> the rest of the space?

Sorry not aware of any.

> 4. how come it could not read the kernel when the partitioning scheme
> was GPT?Is it because it was raid5 in hardware?

Shouldn't be, I've never had an issue booting from GPT installs even with
much older Dell machines.

I see you have an dell + mfi controller, there was an important FW update
released a week or so back do ensure you have that installed or you'll
suffer from nasty IO stalls.

    Regards
    Steve

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