Re: ZFS for a desktop computer

On Sat, Nov 1, 2008 at 7:17 PM, John Nielsen <lists_at_jnielsen.net> wrote:
> On Saturday 01 November 2008, Nicolas Martyanoff wrote:
>> I'm thinking about switching my main desktop to FreeBSD for various
>> reasons (main one, I love it on my laptop and server), and I've been
>> considering using ZFS. I'd like to have a disk-modular system, ie.:
>>
>> - Being able to have mirroring.
>> - Being able to add new disks without effort.
>> - Being able to add new disks AND mirroring disks (spare disks ?) at
>>   the same time.
>>
>> I'm gonna begin with 2x 1TB disks with mirroring, and I'd like to be
>> able to add, if needed, new disks, for example 2x 1.5TB to get 2.5TB
>> diskspace fully mirrored. The whole process shouldn't need to reinstall
>> the system, or to change the slice/partition layout, ie. be totally
>> transparent for the data.
>> And for this particular need, ZFS seems to be the way to go.
>
> I'm happily using ZFS on a 32-bit FreeBSD desktop system (that also plays a
> home server role). It should meet your disk-modularity requirements above,
> with the exception that it's not possible to add disks to a raidZ set
> (though it is possible to add additional sets to the same zpool).
>
>> However, I'm a bit worried about FreeBSD's ZFS implementation:
>>
>> - I've got a 64bits dual core 2GHz CPU, but can't use an amd64 FreeBSD
>>   since Xen, NVidia drivers and wine don't work on it; but ZFS is said
>>   to be unsuitable for i386.
>
> That's overstating the case. The extra memory headroom on amd64 may make
> things simpler, but it's certianly possible to run ZFS on FreeBSD i386 as
> long as you have a couple gigs of RAM (I actually only have 1.5 GB) and
> follow the tuning guidelines. You should also be willing to monitor your
> system and go through one or two fine-tuning cycles
>
>> - It's said you can't boot from a ZFS pool.
>
> There are patches available to allow this but frankly I don't see the

Can you point out those patches? Thx

> appeal. I think it makes much more sense to have / (including /boot) be a
> regular UFS2 filesystem on a small partition. If something goes wrong you
> can boot from a CD or single-user and not have to worry about getting your
> ZFS pools back online before you can even start troubleshooting the system.
> Since (unlike Solaris) FreeBSD doesn't force you to dedicate whole disks to
> ZFS, this is a viable option. As Miroslav mentioned you can make a small
> root partition on two disks and set them up as a gmirror, leaving the
> remainder of the disks available for  your zpool(s).
>
>> So could you please tell me if using ZFS is ok for me, or should I use
>> a gmirror system (but I don't think I can easily add new disks to this).
>
> You could get most if not all of what you're after with gmirror, gvirstor,
> gjournal, etc but it sounds like ZFS is really what you're after and I
> think you'll be fine. I haven't actually added any disks to my setup since
> I switched to ZFS but it's nice knowing that I can. Add to that cheap
> snapshots, checksumming and self-healing and easy administration and I tink
> it's an easy sale.
>
> JN




-- 
Joao Barros