ZFS boot

[Nate Eldredge]

On Sat, 11 Oct 2008, Pegasus Mc Cleaft wrote:

>> FWIW, my system is amd64 with 1 G of memory, which the page implies is
>> insufficient.  Is it really?
>
> 	This may be purely subjective, as I have never bench marked the speeds, but
> when I was first testing zfs on a i386 machine with 1gig ram, I thought the
> performance was mediocre. However, when I loaded the system on a quad core -
> core2 with 8 gigs ram, I was quite impressed. I put localized changes in my
> /boot/loader.conf to give the kernel more breathing room and disabled the
> prefetch for zfs.
>
> #more loader.conf
> vm.kmem_size_max="1073741824"
> vm.kmem_size="1073741824"
> vfs.zfs.prefetch_disable=1

I was somewhat confused by the suggestions on the wiki.  Do the kmem_size 
sysctls affect the allocation of *memory* or of *address space*?  It seems 
a bit much to reserve 1 G of memory solely for the use of the kernel, 
expecially in my case when that's all I have :)  But on amd64, it's 
welcome to have terabytes of address space if it will help.

> 	The best advice I can give is for you to find an old machine and test-bed zfs
> for yourself. I personally have been pleased with it and It has saved my
> machines data 4 times already (dieing hardware, unexpected power bounces, etc)

Sure, but if my "new" machine isn't studly enough to run it, there's no 
hope for an old machine.  So I'm trying to figure out what I actually 
need.

-- 

Nate Eldredge
neldredge at math.ucsd.edu