Talk:ZFS

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zfs share[edit]

Add section to discuss 'zfs share' feature?

ZIL Mirroring[edit]

There is conflicting information as to whether data loss may occur if an external ZIL fails. Specifically, RackTop Systems claims that no data loss occurs if the ZIL fails.[1] Eatnumber1 (talk) 18:41, 3 January 2013 (UTC) Update: Unability to import a filesystem occurred with zpool version < 19 when a separate log device died at reboot. With version >=19, import is possible with a corrupted log, but some transactions (max 5sec from the last sync period) may be lost. There's no problem with any version when the log dies in regular operating mode. — Preceding unsigned comment added by 141.52.58.15 (talk) 09:17, 20 May 2014 (UTC)

Vandalism revision[edit]

Hey, I was wondering in what way my recent edit providing a non-primary source for the description of OpenZFS as the open-source alternative could be construed as vandalism? At the worst, it's not an amazing quality source, but it certainly isn't vandalism. Paulcd2000 (talk) 01:07, 12 March 2014 (UTC)

Hello there! Please have a look at your edits – in addition to the reference (which is good), why did you introduce words such as "userspaaace", "atomic current" and "spaaace"? Sorry, but such changes automatically qualify your edits as a case of vandalism. — Dsimic (talk | contribs) 12:41, 14 March 2014 (UTC)
... I'm an idiot. I knew having the xkcd string replacement script would come back to bite me at some point. Sorry about that. Paulcd2000 (talk) 17:04, 15 April 2014 (UTC)
No worries. Which string replacement script are you using? — Dsimic (talk | contribs) 02:44, 17 April 2014 (UTC)
I don't know anything about an automatic script, but I'm guessing it has something to do with "Substitutions that make reading the news more fun" http://xkcd.com/1288/ . --70.177.113.174 (talk) 04:52, 14 July 2014 (UTC)
Funny stuff. :) — Dsimic (talk | contribs) 10:14, 15 July 2014 (UTC)

I can't fix it...[edit]

In the last sentence in section "Features" -> "ZFS and hardware RAID", a phrase is given as "disks that do not respond in time (like green hard drives)". AFAIK, energy efficient or "green" drives are no more likely to drop out than regular consumer-class 5400 or 7200 drives, so this is not an appropriate way of wording the idea. The entire sentence should probably be reworded, but I unfortunately don't have the creativity to do so. DraugTheWhopper (talk) 16:35, 29 March 2014 (UTC)

Your assumption is incorrect, sorry. Some drives save energy by powering down in a generally unstoppable way, causing them to sometimes time out from an array. The debacle is about as infamous as the 4k issue, namely with the popular WD Green series. — Smuckola (Email) (Talk) 16:40, 29 March 2014 (UTC)
But is that actually what's happening? I was strongly under the impression that it wasn't spin-down causing problems, but rather extended non-communicative error recovery. I know some people claim it's a problem, but I haven't seen official statements or lab tests. Besides, its still a poorly worded sentence, as "green" and "TLER/CCTL/ERC-enabled" are not, strictly speaking, opposites. Case in point: WD Red is a bit of a hybrid between WD RE and WD Green: Power saving and variable spindle speed from the Green, and ?NASWare? and TLER from the RE. --DraugTheWhopper (talk) 18:07, 29 March 2014 (UTC)
Well, your followup question is different, and I'd have to defer to experts on that. But the originally popularly known fact as of a few years ago, was that WD Green drives (one of the most popular 'green' drives) would time out in a way that was related to energy savings. I'm not sure but other models may have done so as well. This could originally be alleviated by obtaining software that can toggle the TLER setting. Anyway, I just edited the section in question, so does that address your request for increased precision in prose? — Smuckola (Email) (Talk) 19:00, 29 March 2014 (UTC)
I'm still skeptical of the technicalities, but yes, the wording is better now. Thanks! On a side note, is it appropriate to have a comma trailing after "consumer grade"? DraugTheWhopper (talk) 19:13, 29 March 2014 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── Hello there! Please, have a look at this excerpt from the hdparm man page, which explains pretty well the exact behavior of WD Green HDDs:

-J Get/set the Western Digital (WD) Green Drive's "idle3" timeout
   value. This timeout controls how often the drive parks its
   heads and enters a low power consumption state. The factory
   default is eight (8) seconds, which is a very poor choice for
   use with Linux. Leaving it at the default will result in
   hundreds of thousands of head load/unload cycles in a very
   short period of time. The drive mechanism is only rated for
   300,000 to 1,000,000 cycles, so leaving it at the default
   could result in premature failure, not to mention the
   performance impact of the drive often having to wake-up before
   doing routine I/O.
   WD supply [sic] a WDIDLE3.EXE DOS utility for tweaking this setting,
   and you should use that program instead of hdparm if at all
   possible. The reverse-engineered implementation in hdparm is
   not as complete as the original official program, even though
   it does seem to work on at a least a few drives. A full power
   cycle is required for any change in setting to take effect,
   regardless of which program is used to tweak things.
   A setting of 30 seconds is recommended for Linux use.
   Permitted values are from 8 to 12 seconds, and from 30 to 300
   seconds in 30-second increments. Specify a value of zero (0)
   to disable the WD idle3 timer completely (NOT RECOMMENDED!).

In a few words, it's all about WD Green drives going into a low-power state, somewhat similar to laptop HDDs, what requires some time for the HDD to wake up later making it highly possible to drop out of a RAID. However, that sleep timeout is configurable, what makes WD Green drives perfectly suitable for RAID configurations – at least in Linux which performs periodic background flushes to HDDs. Those flushes, when combined with increased sleep timeout, would keep WD Green HDDs from entering the low-power state. — Dsimic (talk | contribs) 19:48, 31 March 2014 (UTC)

Description of OpenZFS[edit]

Hey Schily! Sorry for going back and forth on the line that describes OpenZFS, I've ended up with putting together another condensed description of OpenZFS – it leaves pretty much no space for different meanings, and I hope you'll find it good enough. In a few words, OpenZFS isn't a fork as it produces no actual source code and serves only as an umbrella project that brings tohether other projects (or companies) that deal with ZFS directly. Of course, I'm more than open for further discussion. — Dsimic (talk | contribs) 13:28, 25 August 2014 (UTC)

The text is now better, it still could be enhanced. The existing code is and must be a fork of the Sun original because only the code from Sun grants via the CDDL royalty free access to the related patents. Whether all patents are valid is another question as the basic idea of ZFS is based on my master thesis that was written between late 1988 and May 1991 and published in May 1991 . This is the reason why all patents from Netapp that were used when Netapp tried to sue Sun for ZFS are invalid as well.
We have another problem with OpenZFS as OpenZfs does not really bring people together. There is no own repository and Illumos is a Solaris-ON fork that meanwhile deviates too much from the OpenSolaris original to be able to serve as a master copy. The most important information that would be needed by ZFS developers is not available: the explanation for the extension system. It thus is not possible to check whether the people at Illumos have been able to find a way that allows enhancements from different vendors to co-exist. Schily (talk) 14:04, 25 August 2014 (UTC)
That sounds really interesting, I'll dare to ask have you managed to monetize the concepts from your master thesis? :) You're right that OpenZFS produces no source code, and that's what I was saying all the time, if you agree. Instead, OpenZFS aims to bring different projects/companies/people together, including the handling of a mess created around ZFS pool versions and feature flags (what leads to extensions you refer to), and the time will tell how successful or not the OpenZFS initiative was. That said, OpenZFS is more of a soft skills management movement, so to speak, which aims to do something. — Dsimic (talk | contribs) 14:28, 25 August 2014 (UTC)
The development of my "WormFS" was payed by H.Berthold AG that went bankrupt in August 1993. That prevented a commercial use of the original. Schily (talk) 16:33, 25 August 2014 (UTC)
Too bad it's in German. :( Wait a second, are you Jörg Schilling? — Dsimic (talk | contribs) 21:26, 25 August 2014 (UTC)
German was the language of science until 1945 and this did not change because of the German scrientists... if the content is interesting, people still read German. The people from Sun in California had no problems with reading the text,-) I have been told that the thesis has been read not only by the ZFS people but by filesystem people in general as it includes the only descriptions for the VFS interface. You see, I did more than some people like to have in the WP article. Schily (talk) 12:05, 26 August 2014 (UTC)

Size of (Fletcher-based) checksum?[edit]

If anyone knows the EXACT size of the (Fletcher-based) checksum that is stated in section ZFS#ZFS_data_integrity, please add it to the article. Thanks! • SbmeirowTalk • 18:32, 11 September 2014 (UTC)

The exact size is specified in the source code. Check openzfs source code. — Preceding unsigned comment added by 213.89.27.171 (talk) 14:57, 17 August 2015 (UTC)

ZFS on Linux articles[edit]

Here are a couple of useful NEW links that someone might be able to use as references.

SbmeirowTalk • 18:36, 11 September 2014 (UTC)

Unfortunately, blogs (in general) aren't considered to be reliable references. However, IIRC there's a recent LWN.net article that describes current state of the ZFS on Linux. — Dsimic (talk | contribs) 07:30, 14 September 2014 (UTC)

Max File name length[edit]

255 bytes is the same as 255 ASCII characters, this should be changed to be less misleading to users. — Preceding unsigned comment added by Bumblebritches57 (talkcontribs) 09:14, 28 February 2015 (UTC)

Hello! Yeah, but what about the Unicode crap (read: multibyte characters) people want to use in their file names? — Dsimic (talk | contribs) 07:48, 1 March 2015 (UTC)
That is a fairly good point, maybe we can say that it supports 255 ASCII chars, and then expand on that in parentheses? Bumblebritches57 (talk) 05:50, 2 March 2015 (UTC)
Sounds good, please go ahead and I'll review it later. — Dsimic (talk | contribs) 05:59, 2 March 2015 (UTC)

External links modified[edit]

Hello fellow Wikipedians,

I have just added archive links to 2 external links on ZFS. Please take a moment to review my edit. If necessary, add {{cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{nobots|deny=InternetArchiveBot}} to keep me off the page altogether. I made the following changes:

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

YesY Archived sources have been checked to be working

Cheers.—cyberbot IITalk to my owner:Online 15:02, 9 January 2016 (UTC)

Yes check.svg Done, all fine. — Dsimic (talk | contribs) 10:29, 2 February 2016 (UTC)

Block Pointer Rewrite[edit]

What is Block Pointer Rewrite ? It is mentioned in the article, but there is no explanation. I can only find unreliable sources such as https://news.ycombinator.com/item?id=8646590 . --2003:71:CF36:C782:B966:D05B:EDD0:9AD4 (talk) 17:38, 1 February 2016 (UTC)