Register for the iXsystems Community to get an ad-free experience and exclusive discounts in our eBay Store.
Resource icon

Terminology and Abbreviations Primer

Ericloewe

Not-very-passive-but-aggressive
Moderator
Joined
Feb 15, 2014
Messages
16,047
Thanks
3,894
#21
I'm sure @dlavigne can point us towards the process we should follow to suggest a fix.
 

jgreco

Resident Grinch
Moderator
Joined
May 29, 2011
Messages
11,799
Thanks
3,053
#22
Many new users, and even some experienced ZFS pros, mistakenly use the term "ZIL" to refer to a separate ZFS intent log
Here is why:
https://www.freebsd.org/doc/handbook/zfs-term.html#zfs-term-zil

The documentation makes it sound like that and makes no reference to SLOG. I don't point this out to be argumentative, I am actually looking for an answer. Why does the documentation appear to be 'wrong'?
Ummmmmm... well you literally quoted the reason. Even some experienced ZFS pros only ever hear of "ZIL" in relation to this magical speedup device that gets added to ZFS to make it go faster. It's akin to users who think turning on their monitor is "turning on their computer," that that box on their desk is the "hard drive," that the NAT gateway they use is a "router," that the DOCSIS gateway is a "modem," or all the news outlets that refer to cyber criminals as "hackers." There is some kernel of truth combined with a significant misunderstanding of the technical reality, combined with a failure to be corrected.

Many of these are not really important in their ambiguity. I'm pretty sure everyone understands "cable modem," for example. Unfortunately, in the case of ZIL, the term refers both to the in-pool ZIL as well as ZIL maintained on separate log devices. This becomes an important distinction in some cases, and it is confusing when people are talking about "the ZIL" but really mean "the SLOG."
 

Chris Moore

Super Moderator
Moderator
Joined
May 2, 2015
Messages
9,355
Thanks
2,994
#23
well you literally quoted the reason.
One would expect that the "official" documentation at freebsd.org would be the "definitive" answer. I have done enough searching and reading to understand the distinction between the two, but I can see how people get confused if the documentation is wrong. If their answer is wrong, is there a way to get it fixed? I am guessing that other people, besides myself, would look to documentation for answers and it sure would be nice if the documentation could be consistent and correct.
 

Ericloewe

Not-very-passive-but-aggressive
Moderator
Joined
Feb 15, 2014
Messages
16,047
Thanks
3,894
#24
You can file a pull request with a fix and ask someone with a doc commit bit to look it over.
 

jgreco

Resident Grinch
Moderator
Joined
May 29, 2011
Messages
11,799
Thanks
3,053
#25
One would expect that the "official" documentation at freebsd.org would be the "definitive" answer. I have done enough searching and reading to understand the distinction between the two, but I can see how people get confused if the documentation is wrong. If their answer is wrong, is there a way to get it fixed? I am guessing that other people, besides myself, would look to documentation for answers and it sure would be nice if the documentation could be consistent and correct.
One would expect lots of things that turn out to be a disappointment in reality. When you do this long enough, you become a cynical old grinch.

I largely stopped trying to fight these battles in other people's yards, because it's a lot of work and over time the corrections tend to get un-corrected, as someone else comes along and says "WTF is a SLOG, oh everyone calls that a ZIL" and helpfully "fixes" it. So I set up shop here in the forums, and as a senior member I have the credibility to say my stuff, provide explanation and justification, and therefore I can address this issue where it matters to me. I pursue this sort of thing here in the forums where I find that the misuse of terms in technical discussions is jarring and unhelpful to clear communication, but I also realize some people view it as pointless pedantry. I do hope that the reams of crap I post are in some way helpful, educational, or useful to people, but there are only so many hours in the day and recently I haven't even had the time to post much here, much less try to fix the world elsewhere.

I am glad you understand the difference between SLOG and ZIL, and I'm pleased to see you identifying a deficiency like this. I have no objections if you wish to pursue such a correction in the docs and I welcome and invite you to use any of the material I've written regarding SLOG and ZIL if it happens to be helpful. I heartily approve of technical correctness.
 

Chris Moore

Super Moderator
Moderator
Joined
May 2, 2015
Messages
9,355
Thanks
2,994
#26
Top