Some laptops have pc card and expresscard slots, and you can get an adapter for 
sd card, so you could set up your os non mirrored and just set up home on a 
pair of sd cards. Something like

I've done this in the past, variations of this, including using a partition and 
a usb stick:
Wow, where did the time go, that was almost 5 years ago...

Anyway, i pretty much ditched carrying the laptop, the current one i have is 
too heavy (m4400). But it does run really nicely sol11 and openindiana. The 
m4400 is set up with 2 drives, not mirrored. I'm tempted to put a sandforce 
based ssd for faster booting and better zfs perf for demos. Then i have an 
sdcard and expresscard adapter for sd. This gives me 16gb mirrored for my 
documents, which is plenty. 

Sent from my iPad

On Nov 8, 2011, at 12:05 PM, Jim Klimov <> wrote:

> Hello all,
>  I am thinking about a new laptop. I see that there are
> a number of higher-performance models (incidenatlly, they
> are also marketed as "gamer" ones) which offer two SATA
> 2.5" bays and an SD flash card slot. Vendors usually
> position the two-HDD bay part as either "get lots of
> capacity with RAID0 over two HDDs, or get some capacity
> and some performance by mixing one HDD with one SSD".
> Some vendors go as far as suggesting a highest performance
> with RAID0 over two SSDs.
>  Now, if I were to use this for work with ZFS on an
> OpenSolaris-descendant OS, and I like my data enough
> to want it mirrored, but still I want an SSD performance
> boost (i.e. to run VMs in real-time), I seem to have
> a number of options:
> 1) Use a ZFS mirror of two SSDs
>   - seems too pricey
> 2) Use a HDD with redundant data (copies=2 or mirroring
>   over two partitions), and an SSD for L2ARC (+maybe ZIL)
>   - possible unreliability if the only HDD breaks
> 3) Use a ZFS mirror of two HDDs
>   - lowest performance
> 4) Use a ZFS mirror of two HDDs and an SD card for L2ARC.
>   Perhaps add another "built-in flash card" with PCMCIA
>   adapters for CF, etc.
> Now, there is a couple of question points for me here.
> One was raised in my recent questions about CF ports in a
> Thumper. The general reply was that even high-performance
> CF cards are aimed for "linear" RW patterns and may be
> slower than HDDs for random access needed as L2ARCs, so
> flash cards may actually lower the system performance.
> I wonder if the same is the case with SD cards, and/or
> if anyone encountered (and can advise) some CF/SD cards
> with good random access performance (better than HDD
> random IOPS). Perhaps an extra IO path can be beneficial
> even if random performances are on the same scale - HDDs
> would have less work anyway and can perform better with
> their other tasks?
> On another hand, how would current ZFS behave if someone
> ejects an L2ARC device (flash card) and replaces it with
> another unsuspecting card, i.e. one from a photo camera?
> Would ZFS automatically replace the L2ARC device and
> kill the photos, or would the cache be disabled with
> no fatal implication for the pools nor for the other
> card? Ultimately, when the ex-L2ARC card gets plugged
> back in, would ZFS automagically attach it as the cache
> device, or does this have to be done manually?
> Second question regards single-HDD reliability: I can
> do ZFS mirroring over two partitions/slices, or I can
> configure "copies=2" for the datasets. Either way I
> think I can get protection from bad blocks of whatever
> nature, as long as the spindle spins. Can these two
> methods be considered equivalent, or is one preferred
> (and for what reason)?
> Also, how do other list readers place and solve their
> preferences with their OpenSolaris-based laptops? ;)
> Thanks,
> //Jim Klimov
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