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Please remind me not to let you administer my filesystems.

http://jrs-s.net/2015/02/03/will-zfs-and-non-ecc-ram-kill-your-data/

https://forums.freenas.org/index.php?threads/ecc-vs-non-ecc-ram-and-zfs.15449/

https://arstechnica.com/civis/viewtopic.php?f=2&t=1235679&p=26303271#p26303271

https://www.csparks.com/ZFS%20Without%20Tears.html

You can install legacy boot option rom without removing the screw Tepples. :P

Based on the results of a Google search for legacy boot chromebook, such as this and this and this, I'm under the impression that legacy boot can be reached only from developer mode, which we've established is fragile, and it tends to corrupt itself when the battery runs dry. What keywords should I have used to find a guide to setting up legacy boot on Chromebook?

Also, you normally dont need to disassemble the hinge mechanism to get to the screw. It is usually accessible just after removing the back of the clamshell.

That's not the scenario I had in mind. What I had in mind was that the hinge would eventually develop a fault through wear and tear unrelated to the installation of custom firmware, and then a warranty service program trying to minimize costs might notice that the firmware isn't stock and refuse to service the hinge on grounds of having modified the firmware.

I was going to update my FeeNAS server today. I guess I shouldn’t have wasted so much time in the foums!

I spent half the day in the forums to confirm switching from a single six-drive RAIDZ3 vdev to three two-drive mirror vdevs. Found this article that convinced me.

http://jrs-s.net/2015/02/06/zfs-you-should-use-mirror-vdevs-not-raidz/

Tomorrow I'll spend half the day cleaning up my home office from blowing out two years of dust bunnies from inside the file server.

ZFS requires an absurd amount of RAM dedicated to managing storage.

And ZFS needs ECC RAM, errors must be detected because with ZFS there can be a write to the hard drive to fix a mismatched "checksum" when the software is requesting a read. Bad RAM is a much bigger problem with ZFS than other file systems. Its really not a good idea for consumer hardware.

Disputed, to put it mildly.

http://research.cs.wisc.edu/ad...

ZFS requires an absurd amount of RAM dedicated to managing storage.

And ZFS needs ECC RAM, errors must be detected because with ZFS there can be a write to the hard drive to fix a mismatched "checksum" when the software is requesting a read. Bad RAM is a much bigger problem with ZFS than other file systems. Its really not a good idea for consumer hardware.

Disputed, to put it mildly.

ZFS: You should use mirror vdevs, not RAIDZ

Guess what? The entire rsync.net service is built on top of RAID-Z3, if I read their promotional portal correctly.

That sounds bad, but I think it actually makes sense. From the article you linked to, slightly edited:

* don’t be greedy. 50% storage efficiency is plenty
[because]
  * a pool of mirrors is easier to manage, maintain, live with, and upgrade than a RAIDZ stripe.

From that, it actually makes sense that when the major cost is storage, it might be worth it to trade away the "easiness" of mirrors for the lower cost of RAIDZ.

Yeah, he writes okay pieces, but it kind of annoys me when he throws up blanket advice and then practically trips over himself extolling the opposite.

ZFS: You should use mirror vdevs, not RAIDZ

Guess what? The entire rsync.net service is built on top of RAID-Z3, if I read their promotional portal correctly.

One use case I can see for this is using ZFS to back up Postgres databases. I'm not the only person to think this might be a good idea. A while back, I listened to this talk, which I really enjoyed:

Keith Paskett: PostgreSQL on ZFS

On hard experience, he's particularly wary about the "drop table" oops disaster scenario.

Keith Paskett bio

* infrared radiometric calibration chambers Space Dynamics Laboratory
* helped develop Utah State University's Climate data server
* National Climate Data Center validated climate data
* all stored in PostgreSQL of course

--You can definitely add more disks if you are using mirrored drives in your pool, instead of RAIDZ. I created a Linux ZFS RAID0 (no redundancy) pool with 2 brand-new drives initially, then bought 2 more drives of the same brand and capacity a month later, and upgraded the pool in-place with no downtime to a zRAID10.

--If I want to expand the size of the pool, I can just add 2 more disks in a mirrored configuration.

# zpool add mirpool mirror ata-ST9500420AS_5VJDN5KL ata-ST9500420AS_5VJDN5KJ

--Note that this syntax is using Linux /dev/disk/by-id devices.

--There are some caveats and best-practices that one should read up on, for instance using ashift=12 with 4K sector drives; and using GPT partition tables on ZFS disks; but ZFS has by far been the most reliable and useful filesystem I've ever used.

REF:
https://blogs.oracle.com/partn...
http://zfsonlinux.org/faq.html
http://jrs-s.net/2015/02/06/zf...
https://jsosic.wordpress.com/2...