YIKES! I am going to need some help

Matthew Seaman matthew at FreeBSD.org
Mon Sep 12 07:19:47 UTC 2016

On 11/09/2016 15:41, Baho Utot wrote:
> - Install 4  1TB hard drives for ZFS raid Z array.
> - Load FreeBSD ( current USB image ) from USB using ZFS.
>         Will the installer do this or do I need to tweak it?

The installer will create a RAIDZ array for you no problem, and FreeBSD
will be able to boot from it.

>         Will my present 10.3 version still function while I am setting
> this up?

I don't see why not.  I'm not sure how you're intending to switch
between each of these three different OSes while you're building your
RAIDZ based system -- normally you'ld use something like grub, but given
this is only intended to be a temporary state, you probably don't want
the bother of setting that up.

If you want to copy files between the existing 10.3 setup and the new
11.0 RAIDZ then it will be pretty trivial to boot into one of those OSes
and mount the filesystems from the other -- but there are pitfalls to
booting into 10.3 and trying to mount the 11.0 files:

- When you import the 11.0 ZFS remember to use the '-R /mnt' flags, or
it will overlay your exising root directory

- As I recall, there are some new feature flags in ZFS under 11.0 that
aren't supported in 10.x, which you need to avoid using to maintain
compatibility.  See zpool-features(7) for the full details.

Best to render the whole question moot and boot into 11.0 and then mount
any 10.3 filesystems onto that.

>         I will have win7 on the first primary drive an SSD and then
> remove the second drive after I get this going.
>         I want to create filesystems on the Raid Z array like /usr/home
> /usr/ports /usr/ports/packages etc.
>             You can suggest any other filesystems if it will be helpful.

One thing you might want to consider is using some space on your SSDs
for a separate ZIL and/or ARC device -- this can give you a significant
performance boost, although how much does depend greatly on your
workload and mix of files.

The other thing when creating ZFSes is to resist the temptation to make
huge numbers of them.  Just because you can, doesn't mean that you
should.  Given the shared storage nature of ZFS, you really only need a
separate ZFS as a hook to apply different flags to a specific tree of
files.  On the whole, it is easier to manage one big ZFS than many small



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