[OmniOS-discuss] Where to Run Omni

[Saso Kiselkov]

On 2/3/14, 3:06 PM, Matthew Mabis wrote:
> 
> Hello,
> 
> I have a few questions about a project that i am trying to work on, needless to say i have 1 80GB SSD Drive that i can fit in this case, the rest of the drives are a RaidZ2 configuration and there cannot be anymore added Disks to this system period!
> 
> My goal is to make the SSD capable of making NFS run better (Slog/ZIL/L2ARC) whatever... but i need the OS to go somewhere!  
> 
> My Questions are
> 
> 1) Splitting the SSD into partitions and running is that bad i always heard it was my question is why?
> 2) Can Omni be run from say a 32GB USB3 key directly?
> 3) What options do i have here outside of adding a drive.
> 
> I have SATA Slots on the mobo just no place to add an additional drive!

Yes, you can partition the SSD and it works okay. For the OS, set aside
something like 10GB and turn on compression. Although the standard
installer doesn't let you set compression on the root pool before
starting installation, there's a trick to doing it. Before firing up the
installation, get a shell from the installer menu and run the following
commands:

# screen
# while ! zpool set compress=lz4 rpool; do sleep 1; done

(after this hit 'Ctrl-A' + 'D' and type 'exit' to return to the
installer menu and leave the loop running)

The loop will try to set compression on the newly created root pool as
soon as the installer creates it, so that the OS's data itself will be
installed compressed.

For slog (aka ZIL) you don't need much - usually around 1-2GB is more
than enough, since it only needs to hold the sync write data from the
last transaction (by default: the last 5 seconds).

Use the rest of the SSD for L2ARC. Depending on the SSD type you may
also want to keep around 10-20% of the SSD unallocated, so that the
garbage collector on the controller always has blocks available it can
pre-erase - this can boost long-term slog performance quite a bit. YMMV

Cheers,
-- 
Saso