ZFS...

Paul Mather
2019-05-07T13:03:00Z

On May 7, 2019, at 1:02 AM, Michelle Sullivan <michelle at sorbs.net>
wrote:

>> On 07 May 2019, at 10:53, Paul Mather <paul at
gromit.dlib.vt.edu> wrote:
>>
>>> On May 6, 2019, at 10:14 AM, Michelle Sullivan <michelle at
sorbs.net>
>>> wrote:
>>>
>>> My issue here (and not really what the blog is about) FreeBSD is
>>> defaulting to it.
>>
>> You've said this at least twice now in this thread so I'm
assuming
>> you're asserting it to be true.
>>
>> As of FreeBSD 12.0-RELEASE (and all earlier releases), FreeBSD does NOT
>> default to ZFS.
>>
>> The images distributed by freebsd.org, e.g., Vagrant boxes, ARM images,
>> EC2 instances, etc., contain disk images where FreeBSD resides on UFS.
>> For example, here's what you end up with when you launch a
12.0-RELEASE
>> instance using defaults on AWS (us-east-1 region:
ami-03b0f822e17669866):
>>
>> root at freebsd:/usr/home/ec2-user # gpart show
>> =>       3  20971509  ada0  GPT  (10G)
>>         3       123     1  freebsd-boot  (62K)
>>       126  20971386     2  freebsd-ufs  (10G)
>>
>> And this is what you get when you "vagrant up" the
>> freebsd/FreeBSD-12.0-RELEASE box:
>>
>> root at freebsd:/home/vagrant # gpart show
>> =>       3  65013755  ada0  GPT  (31G)
>>         3       123     1  freebsd-boot  (62K)
>>       126   2097152     2  freebsd-swap  (1.0G)
>>   2097278  62914560     3  freebsd-ufs  (30G)
>>  65011838      1920        - free -  (960K)
>>
>>
>> When you install from the 12.0-RELEASE ISO, the first option listed
>> during the partitioning stage is "Auto (UFS)  Guided Disk
Setup".  The
>> last option listed---after "Open a shell and partition by
hand" is "Auto
>> (ZFS)  Guided Root-on-ZFS".  In other words, you have to skip over
UFS
>> and manual partitioning to select the ZFS install option.
>>
>> So, I don't see what evidence there is that FreeBSD is defaulting
to
>> ZFS.  It hasn't up to now. Will FreeBSD 13 default to ZFS?
>
> Umm.. well I install by memory stick images and I had a 10.2 and an 11.0
> both of which had root on zfs as the default.. I had to manually change
> them.  I haven?t looked at anything later... so did something change?  Am
> I in cloud cookoo land?


I don't know about that, but you may well be misremembering.  I just pulled
down the 10.2 and 11.0 installers from
http://ftp-archive.freebsd.org/pub/FreeBSD-Archive/old-releases and in both
cases the choices listed in the "Partitioning" step are the same as in
the
current 12.0 installer: "Auto (UFS)  Guided Disk Setup" is listed
first and
selected by default.  "Auto (ZFS)  Guided Root-on-ZFS" is listed last
(you
have to skip past other options such as manually partitioning by hand to
select it).

I'm confident in saying that ZFS is (or was) not the default partitioning
option in either 10.2 or 11.0 as officially released by FreeBSD.

Did you use a custom installer you made yourself when installing 10.2 or
11.0?


>
>>> FreeBSD used to be targeted at enterprise and devs (which is where
I
>>> found it)... however the last few years have been a big push into
the
>>> consumer (compete with Linux) market.. so you have an OS that
concerns
>>> itself with the desktop and upgrade after upgrade after upgrade
(not
>>> just patching security issues, but upgrades as well.. just like
windows
>>> and OSX)... I get it.. the money is in the keeping of the user
base..
>>> but then you install a file system which is dangerous on a single
disk
>>> by default... dangerous because it?s trusted and ?can?t fail? ..
until
>>> it goes titsup.com and then the entire drive is lost and all the
data
>>> on it..  it?s the double standard... advocate you need ECC ram,
>>> multiple vdevs etc, then single drive it.. sorry.. which one is it?
>>> Gaaaaaarrrrrrrgggghhhhhhh!
>>
>>
>> As people have pointed out elsewhere in this thread, it's false to
claim
>> that ZFS is unsafe on consumer hardware.  It's no less safe than
UFS on
>> single-disk setups.
>>
>> Because anecdote is not evidence, I will refrain from saying,
"I've lost
>> far more data on UFS than I have on ZFS (especially when SUJ was
shaking
>> out its bugs)..." >;-)
>>
>> What I will agree with is that, probably due to its relative youth, ZFS
>> has less forensics/data recovery tools than UFS.  I'm sure this
will
>> improve as time goes on.  (I even posted a link to an article
describing
>> someone adding ZFS support to a forensics toolkit earlier in this
>> thread.)
>
> The problem I see with that statement is that the zfs dev mailing lists
> constantly and consistently following the line of, the data is always
> right there is no need for a ?fsck? (which I actually get) but it?s used
> to shut down every thread... the irony is I?m now installing windows 7
> and SP1 on a usb stick (well it?s actually installed, but sp1 isn?t
> finished yet) so I can install a zfs data recovery tool which reports to
> be able to ?walk the data? to retrieve all the files...  the irony eh...
> install windows7 on a usb stick to recover a FreeBSD installed zfs
> filesystem...  will let you know if the tool works, but as it was
> recommended by a dev I?m hopeful... have another array (with zfs I might
> add) loaded and ready to go... if the data recovery is successful I?ll
> blow away the original machine and work out what OS and drive setup will
> be safe for the data in the future.  I might even put FreeBSD and zfs
> back on it, but if I do it won?t be in the current Zraid2 config.


There is no more irony in installing a data recovery tool to recover a
trashed ZFS pool than there is in installing one to recover a trashed UFS
file system.  No file system is bulletproof, which is why everyone I know
recommends a backup/disaster recovery strategy commensurate with the value
you place on your data.  There WILL be some combination of events that will
lead to irretrievable data loss.  Your extraordinary sequence of mishaps
apparently met the threshold for ZFS on your setup.

I don't see how any of this leads to the conclusion that ZFS is
"dangerous"
to use as a file system.  What I believe is dangerous is relying on a
post-mortem crash data recovery methodology as a substitute for a backup
strategy for data that, in hindsight, is considered important enough to
keep.  No matter how resilient ZFS or UFS may be, they are no substitute
for backups when it comes to data you care about.  (File system resiliency
will not protect you, e.g., from Ransomware or other malicious or
accidental acts of data destruction.)

Cheers,

Paul.