ZFS-inly server and dedicated ZIL

[Lawrence K. Chen, P.Eng.]

----- Original Message -----
> > On my home system, I currently have a pair of SSDs....each with 7
> > partitions.... 5 tiny ones for mirror ZILs for the other zpools in
> > my system,
> > the mirrored root pool and partitions to be L2ARC for the two
> > zpools in my
> > system that I'm using dedup in.  (there's currently only 4 zpools
> > in my
> > system, including the root....but I had originally envisioned the
> > possibility
> > of adding additional external jbod arrays....)
> 
> What is not clear for me is why one could want more than one pool in
> one
> machine?
> 
> Thanks for your comments, will test further.
> 

Well, before ZFS it was common (best) practice everywhere I've been that the OS is separate from the rest of the system.  Either when it was just a separate disk, to a separate VG, to now where its a separate zpool.  typically at work, we have root pool, local disk pool (typically 2 drives mirrored, though we have boxes with more than 4 internal drives.), plus a zpool of SAN storage.  Alternatively we have a system where the other local drives are in some kind of raidz pool.)

There's also the part where root pool is limited to a disk or mirrored, Solaris can't boot from a raidz root pool.  Made things wasteful in the Thumper, until they added a compact flash option.

It has only been recently that the practice is losing favor....now that systems are shipping with 300GB drives or larger.

But my home system started with a single 120GB SSD for root pool (cut up for swap, root pool and cache, for a mirrored pool) and a pair of internal 1.5TB drives mirrored, and an external set of 4 - 1.5TB drives in a raidz pool, it later got 6 - 2TB drives in a raidz2 pool.  I later went to a pair of 120GB SSDs, redivvy'd the swap as a bunch of small partitions for mirrored ZILs and added cache to my raidz pool.

The mix of drive sizes is another reason for having more than one zpool....if you mix with mirror or raidz#, the smallest drive limits what the total capacity can be.

Also originally this was a Windows machine with just the 2 x 1.5TB disks mirrored.... as single C drive (I had debated repartitioning it like I had done with my previous Windows machine....wish I had.)  Feb 14, 2012....it had autopatched itself overnight and now the drive was corrupt the only only option in the OEM disk was revert to factory (bought a full copy, but upgrade install requires the system boot first)  I could reinstall the OS, but I want all my data back first.

The 4 - 1.5TB drives had been in RAID5 under windows, but FreeBSD would only see the drives individually...not as the single RAID5 logical.

A couple months ago the same thing happened to another Windows machine (at work.)  Now the only Windows I run are in VirtualBox.  This system is a pair 2TB drives, but I have it divided into two zpools.  I've corrupted zpools on this system twice, until I upgraded the BIOS and it detected a bad DIMM.