Comments on: FreeNAS: A Worst Practices Guide

By: Michael Dexter

Michael Dexter — Fri, 19 Feb 2021 20:19:27 +0000

In reply to Matt. Matt, If your hardware RAID card does not support HBA mode, you can generally create a single disk stripe of each disk, and be sure to disable any write caches. Many cards will mask SMART data from the disks but this will give ZFS full control of them. If this is not an option, a dedicated HBA as simple as the LSI SAS9211-8i or better, plus cables, is the best way to go. A zpool on independent disks is portable between FreeNAS/TrueNAS systems, and even other operating systems that support ZFS. On the other hand, many RAID cards are very particular about tying the specific card and its firmware version to the configured disks.

By: Matt

Matt — Sat, 06 Feb 2021 07:24:41 +0000

I am new to zfs and freenas/truenas and found this blog post interesting.
It would be nice to have an article describing how to use zfs with hardware raid and its best practices.
Assume you have a raid card built in and it is not possible to run hba mode. But I still want to use freenas/truenas with zfs snapshots, compression and so on.
I mean zfs is just a filesystem with nice features and it doesn’t require you to use its software raid features.
Does it mean that I should choose another filesystem, and not use freenas/truenas, if my only option is hardware raid?

By: Joon Lee

Joon Lee — Thu, 13 Sep 2018 23:19:53 +0000

In reply to Jeremy. Yes, the fundamental best and worst practices have never changed.

By: sunrunner20

sunrunner20 — Thu, 02 Aug 2018 22:43:12 +0000

In reply to Jeremy. These apply to ZFS in general. They are not specific to a FreeNAS version, or even to FreeBSD. The same applies to ZFS on Illumos, Linux, and any other OSs with a ZFS implementation.

By: Jeremy

Jeremy — Tue, 15 May 2018 14:38:51 +0000

Are these Worst Practices based off of FreeNAS 9+? If so, do they still apply to FreeNAS 11? I have a Dell R320 that has 7.2K SATA drives (4x2TB) and would like to utilize it simply for an annual backup from Veeam (so it would be written to this storage device once a year).

By: Jesper H Hansen

Jesper H Hansen — Thu, 11 Jan 2018 12:08:17 +0000

In reply to Joe. Nope, i have a DELL SRV with NONE dell HDD and no issues with red lights flashing ;-)

By: Joe

Joe — Wed, 30 Aug 2017 14:58:28 +0000

In reply to BobJ. dell server?? now days don't they blink red if you use a non DELL HDD?? and dell ones cost like X2-X3 more then an non DELL one.

By: konzty

konzty — Mon, 14 Nov 2016 18:26:24 +0000

Hi!
this article is lovely – I love the “Worst Practise” approach to a topic like this. You’ve held the article straight forward with no bullshit and no marketing *bla*.
I’ve worked with ZFS (on Sun Solaris & now Oracle Solaris) professionally since around September 2007, hosting file servers for Unix and Windows clients as well as zvols used as raw devices for databases. I was like: “No help needed, I know my way around.” when I finally bought a few pieces of hardware to suplement a few other pieces of hardware in order to build a home NAS for the wife and I – main intention: Backup of computers and bit rot immune data storage for fotos and other memories.
Well I’ve setup a system based on an Athlon X4 845 with a neat mini ITX board in a neat mini ITX case, with 3 disks of 2 TB – during OS trials I decided to give FreeNAS a go. I have to tell you: I love it. … @ work I do every adminstrative task of our systems on the shell. … but @ home? I don’t want to work at home. *Enter your WebUI* – I can only say: “Well done.”
So how did I stumble over your post?
Had created my volumes, with dedupe and compression, all the way. I started backing up my PC to my NAS and everything was fine, copied 2.2 Tib over night there, all cool. … today I wanted to backup my wifes laptop:
400-800 MBit/s of ethernet throughput for about 10 seconds, … then zero for about 30 seconds … then again: 400-800 MBit/s … Tried with my own laptop: same behaviour. Tried with different payload: same behaviour. … Thought about configuration: What about dedupe?! I didn’t ask myself wether I had enough memory or not to acutally use dedupe and what would happen if I would run out of said memory?
Tried turning off dedupe: 400-800 MBit/s … all … the … time. Nice, found the cause. A quick google search later I got on to your site.
Thanks again for this nice article,
Have a nice evening,
K

By: nicklowiczComputers

nicklowiczComputers — Sun, 07 Aug 2016 15:39:35 +0000

In reply to Mark VonFange. This guy knows little about raid! his opinion VS reality somewhat differ. GOOD comeback on his comment about hardware raid. thats a misconception. ever heard of bit-rot? i work in the field and have saw it and this is server with hardware raid! ZFS hopefully will prevent this

By: Mark VonFange

Mark VonFange — Thu, 22 Oct 2015 20:36:38 +0000

In reply to BobJ.

While hardware RAID isn’t evil, it bybasses many of the features found in ZFS that can help you avoid costly drive-recovery services. We’d like to response to your listed benefits as well:
1. I can blink failed drives light – cant do it on my nas zfs box
TrueNAS offers cabinet management out of the box and while there is not an official way with FreeNAS, one can use various HBA blink features just as you would with a RAID HBA (they’re related) and in a pinch do a ‘dd’ read from the drive.
2. I can pull out a drive live then push it back in, nothing bad happens. Its all automated.
Most non-home FreeNAS systems are hot-swappable. If you are talking about rebuilding, a ZFS system will only rebuild the actual data on disk, rather than the full disk in the case of a hardware RAID card. The hardware RAID card has no insights into what file system or data you have on the disk.
3. Battery backed up cache with auto sensing of low battery, will turn off cache if battery fails.
That is good if all RAID cards include the feature but we have seen such caches provide corrupt data that cannot be attributed to on-disk corruption. This probably rare, but we have seen it.
4. Speed – they are fast.
We have seen the same HBA perform around 5% slower with RAID firmware vs. HBA “target” firmware presumably because of the added RAID calculations. This may not apply to all cards but we have seen it in the field.
5. Auto email and also buzzer if a drive fails.
FreeNAS provides this via the GUI and e-mail. Various scripts exist to use a sound device but they are not incorporated into FreeNAS at this time. Any such buzzer would be card-specific.
6. Probably many more things I can’t think of.
We’d love to hear any more information you can provide.
7. Less reliable drives (SATA) vs SAS.
Most HBAs are compatible with both. Do use SAS drives if your budget permits it.
8. Probably many more things I can’t think of.
We’d love to hear any more information you can provide.