Re: [PLUG] FreeNAS vs. Debian for my simple home NAS

["Lee H. Marzke" <lee@marzke.net>]

FYI - OmniOS is built on IllumOS,  which is the open-source replacement
for the defunct OpenSolaris.   I'll have to give that a try.

Nexenta,  Joyent, DataON, Emulux, are all sponsors of IllumOS and Nexenta is
moving to IllumOS shortly as well,  a beta is out.

32bit,  yes Nexenta doesn't even support it.  64 bit only.

Nexenta also cautions against use of De-dup as there are still software issues
especially with small amounts of RAM and turning off de-dup once
enabled.

A vDEV is a Redundant disk ( RAIDZ1 with 2, 3, 4 or more disks )
A zPool is composed by striping across a number of similar vDEV's.

In practice I had one physical Nexenta box with 2 SSD's for OS syspool, and 11
2TB NL-SAS disks set as 5 RAIDZ vDEV's and 1 spare for the data pool.
After 6 months one of the root SSD's failed.  The system was very slow for
about a day as the bad SSD was not completely failed, and that slows
down the whole syspool.   Once the disk was marked as failed,  the
system speed went back to normal, and I was able to remove and
replace the bad disk without re-installing anything.   I've had
several infant SSD failures due to bad wear-leveling firmware.

With SATA,  if any of those disks have their automatic sector relocation
performed by the internal controller and the drive is off-line for too
long, ZFS will remove it from the pool.  Many drives don't allow
you to turn this feature off, BTW.   So, with ZFS,  you need to find
drives that support disabled re-allocation or risk losing your
data when 2 devices decide to do this on their own.

For those with a budget,
Dell has announced supported SKU's for ordering NexentaStor
on production Dell hardware.  From 11TB to 720TB systems.

http://www.nexenta.com/corp/solutions/dell-and-nexenta-storage-solutions

These are all dual-head.
They come with L2ARC and ZIL  ( read/write) cache devices, and
use the cheaper Near-Line SAS (7200 rpm) SAS drives.

Lee

----- Original Message -----
> From: "Morgan Jones" <morgan@morganjones.org>
> To: "Philadelphia Linux User's Group Discussion List" <plug@lists.phillylinux.org>
> Sent: Monday, June 17, 2013 5:35:11 PM
> Subject: Re: [PLUG] FreeNAS vs. Debian for my simple home NAS
> 
> Adam (and Lee),
> 
> If your machine is 32 bit stay away from ZFS at least on FreeBSD.  I
> went through a ton of pain on a P4 machine while experimenting with
> ZFS--it was intolerably unstable.  I upgraded to a 64 bit i3 and all
> problems went away.
> 
> As Lee said ZFS is memory hungry and works better with more.  My ~4tb
> usable machine works fine with 4gb though.  YMMV of course, mine is
> mostly serving timemachine backups, movies, photo archives and a
> simple vmware store.  the big thing I've read is don't use de-dup
> unless you have a ton of memory.
> 
> I had no end of problems with eSATA--drives would fall off and return
> seemingly at random.  My hardware was commodity but reasonable
> quality commodity.  SATA green drives have been no problem if on the
> slow side.
> 
> ZFS will work with with a non-mirrored root disk and you can run it
> without mirroring or RAIDZ (their implementation of RAID5).  You
> will still get snapshotting, dynamic re-sizing, replication etc.  I
> would argue that you should use redundancy but certainly it works
> fine without it.  putting root on zfs is *awesome*.  I have a howto
> somewhere if you are interested.
> 
> I'm not an LVM expert but I would say once you get the hang of it ZFS
> is miles beyond LVM in basically every way.
> 
> ZFS will be fine (albeit perhaps overkill) with just 2 (or even 1)
> spindles.  ZFS gives you the combined speed of both disks in a
> stripe or the speed of one disk in a mirror just like conventional
> raid.  RAIDZ for 2 disks makes no sense in the same way RAID5 makes
> no sense for 2 disks.
> 
> I run without read cache or ZIL and it works just fine.  Though I
> have been meaning to try various levels of caching since watching
> what it does for performance at  a recent devops presentation.
> 
> I tried FreeNAS initially but found myself doing all of my
> configuration on the command line.  I'm a tinkerer, didn't really
> want the gui anyway and was interested to learn ZFS so finally just
> installed FreeBSD which has been a fun diversion from Linux.
> 
> -morgan
> 
> 
> 
> On Jun 17, 2013, at 5:10 PM, Lee H. Marzke wrote:
> 
> > My info below is based on NexentaStor community,  FreeNAS is
> > similiar.
> > 
> > If you use the newer FreeNAS, it's based on ZFS.
> > 
> > You want a LOT of RAM,  perhaps 8G or more.  The extra
> > RAM is used for ARC read cache.
> > 
> > Not sure USB drives work, and they are slow.  External drives
> > should be eSATA. HW RAID controllers need to be shut off as
> > ZFS is software RAID.
> > 
> > ZFS requires a Mirror or RAID configuration.   so with only
> > 2 drives ( RAID-Z2) you'll lose half your capacity.  OK it may
> > not force you to mirror,  but ZFS is designed assuming all your
> > vDEV's are at least two physical devices with optional spare.
> > 
> > Note:  A ZFS NAS is really designed for 2 boot disks and 8 data
> > disks or more
> > with optional SSD for read cache and ZIL.   If you try and run it
> > with low memory and 2 spindles,  not sure how well that will work
> > for you.
> > 
> > I'd suggest sticking with non-ZFS solutions for this.
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > From: "Adam Zion" <azion1995@gmail.com>
> > To: "PLUG" <plug@lists.phillylinux.org>
> > Sent: Monday, June 17, 2013 3:03:04 PM
> > Subject: [PLUG] FreeNAS vs. Debian for my simple home NAS
> > 
> > OK, so I've got my roll-your-own NAS up and running like so:
> > 	â Ancient Dell Dimension (headless after I got everything up and
> > 	running)
> > 	â Crunchbang Linux (Debian-based)
> > 	â SAMBA
> > 	â 2 1 TB USB2 drives (amazingly, the ancient Dell has USB2 ports)
> > 	â SAMBA shares on one of the USBs
> > 	â Nighly rsync copies from one drive to the other to make a de
> > 	facto RAID 1
> > Ain't pretty, and uses a lot more W of electricity than the
> > Raspberry Pi-based NAS would have, but it works.
> > My question is: would there be any advantage to using FreeNAS (or
> > NAS4Free) on this device vs. remaining w/Crunchbang?
> > -Z
> > --
> > Adam+Zion, MSIS, MCSE+I
> > Registered Linux User #471910
> > LinkedIn Profile: http://www.linkedin.com/in/azion1995
> > ___________________________________________________________________________
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