Comments on: ZFS Administration, Part XVI- Getting and Setting Properties https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/ Linux. GNU. Freedom. Thu, 11 Jan 2018 12:06:15 +0000 hourly 1 https://wordpress.org/?v=5.0-alpha-42199 By: Mike Holden https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-269879 Thu, 06 Apr 2017 03:35:48 +0000 http://pthree.org/?p=2950#comment-269879 Hi Aaron, love these references. Just starting with zfs, and this is the best guide by a mile!

Just to note that the groupquota item in the list above references userquota in the notes. Copy&paste error no doubt!

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By: Kal https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-267868 Wed, 23 Nov 2016 02:56:38 +0000 http://pthree.org/?p=2950#comment-267868 I have a few questions regarding the sharenfs property and the zfs share/unshare commands.

Under the explanation for the sharenfs property, you write:
Debian and Ubuntu require a valid export in the /etc/exports file before the daemon will start.

Is that still true?

What's considered *valid*? For instance, if I have a dataset tank/foo, do I need to create an export rule for /tank/foo in /etc/exports, with export options matching the sharenfs property (rw, no_root_squash, etc)?

What happens if the export options don't match between /etc/exports and the sharenfs property?

What's so special about ZFS that they included the sharenfs property and share/unshare commands? Why not let people manage the sharing of the dataset just like any other file system?

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By: Anonymous https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-261017 Sat, 06 Feb 2016 21:55:20 +0000 http://pthree.org/?p=2950#comment-261017 You can clear user defined properties using "zfs inherit", as described in zfs man-page:
"Use the zfs inherit command to clear a user property . If the property is not defined in any parent dataset, it is removed entirely."

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By: Wade https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-245679 Sat, 05 Sep 2015 18:23:10 +0000 http://pthree.org/?p=2950#comment-245679 Dam, my studies of zfs is getting very very complicated. I think I've seen anywhere from 11-15 different dataset size/capacity related properties, depending on the quality of the documentation provided for any given implementation. FYI logicalused and a number of other properties are missing above.

Here's a list I thought was comprehensive but now I know is not:
available
quota
referenced
refquota
refreservation
reservation
used
usedbychildren
usedbydataset
usedbyrefreservation
usedbysnapshots
volsize

Firstly, let me explain my task. I need at least one simple bar graph for each ZFS dataset, however, what the bar graph should represent I think is completely different depending on dataset type and a number of properties. Like if you have a volsize than that should be the 100% mark, the quota could be shown at the appropriate mark and then used space could show the utilization in this single diagram. There are just too many decisions to be made based off these unnormalized variables. It's really difficult and I need some input.

One, big decision. When I show this bar graph for each dataset, do I use the quantities that include the children... and where is a comprehensive definition of child? Can a snapshot have a child? I think I need some drawings, to understand this.

My instinct tells me every single size based variable needs it's place as a bar graph marker point, total or % fill... but man it's proving very difficult to determine which variables to show when and how I can use the variables to actually calculate anything. Like, on most normal file systems Freespace = Total space - minus used space. But on ZFS it's like these calculations are so incredibly complicated they provide each discrete variable you may need, but if the variables were normalized it would be a lot easier! Can anyone help? I'd like to see a list of quick sketches, for each dataset type, of all the bar graph possibilities and/or recommendations depending on all these incredibly complicated factors. Or am I complicating it too much?

Thanks if you got this far! lol

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By: Aaron Toponce https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-228646 Fri, 06 Mar 2015 16:42:39 +0000 http://pthree.org/?p=2950#comment-228646 Looks like some properties have been added since I've created this post. I'll update. Thanks for catching that!

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By: John Naggets https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-228633 Fri, 06 Mar 2015 11:10:43 +0000 http://pthree.org/?p=2950#comment-228633 Just noticed that you are missing the "acltype" property in your documentation. You might want to add it, as for example I need to change it to posixacl in order to use GlusterFS on top of ZFS.

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By: Aaron Toponce https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-227901 Tue, 17 Feb 2015 20:34:45 +0000 http://pthree.org/?p=2950#comment-227901

So what's the difference between a VDEV with quotas and a ZVOL? And how to minimize fragmentation?

I think you mean a "dataset with quotas" rather than a VDEV. A dataset with quotas just has an upper limit on how much storage can be set. A ZVOL actually creates a block device that can be partitioned, formatted, etc. in /dev/ just like any other block device.

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By: Aaron Toponce https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-227900 Tue, 17 Feb 2015 20:32:57 +0000 http://pthree.org/?p=2950#comment-227900

By setting sync=disabled on a ZFS volume, does this mean that there is no ZIL nor any L2ARC, is my interpretation correct here?

By setting "sync=disabled", the ZIL is completely bypassed, and data is written directly to spinning platter. If the ZIL resides on a SLOG, then the SLOG will also be equally bypassed. However, if you have an L2ARC (a cache), writes aren't taken into account here, except to evict pages from RAM to the L2ARC. The L2ARC (should be) is read-heavy. Setting "sync=disabled" has no effect here.

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By: John Naggets https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-227145 Fri, 06 Feb 2015 15:47:07 +0000 http://pthree.org/?p=2950#comment-227145 By setting sync=disabled on a ZFS volume, does this mean that there is no ZIL nor any L2ARC, is my interpretation correct here?

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By: NM https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-227106 Thu, 05 Feb 2015 22:28:54 +0000 http://pthree.org/?p=2950#comment-227106 So what's the difference between a VDEV with quotas and a ZVOL?
And how to minimize fragmentation?

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By: John Naggets https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-225086 Sat, 17 Jan 2015 18:09:35 +0000 http://pthree.org/?p=2950#comment-225086 What about xattr? I read it should be set to xattr=sa but I can't find any mention of "sa" option in your documentation

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By: Anonymous https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-132116 Thu, 03 Apr 2014 21:59:32 +0000 http://pthree.org/?p=2950#comment-132116 zfs inherit seemed to work to get rid of user properties:

root@fs01# zfs set jim:test="testing user properties" tank/stor/jim
root@fs01# zfs get jim:test tank/stor/jim
NAME PROPERTY VALUE SOURCE
tank/stor/jim jim:test testing user properties local
root@fs01# zfs inherit jim:test tank/stor/jim
root@fs01# zfs get jim:test tank/stor/jim
NAME PROPERTY VALUE SOURCE
tank/stor/jim jim:test - -

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By: Aaron Toponce : ZFS Administration, Appendix B- Using USB Drives https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-127471 Tue, 09 Jul 2013 04:08:06 +0000 http://pthree.org/?p=2950#comment-127471 […] Getting and Setting Properties […]

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By: Aaron Toponce : Install ZFS on Debian GNU/Linux https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-125797 Mon, 06 May 2013 00:02:48 +0000 http://pthree.org/?p=2950#comment-125797 [...] Getting and Setting Properties [...]

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By: Aaron Toponce : ZFS Administration, Appendix A- Visualizing The ZFS Intent LOG (ZIL) https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-124831 Fri, 19 Apr 2013 11:03:53 +0000 http://pthree.org/?p=2950#comment-124831 [...] Getting and Setting Properties [...]

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By: Aaron Toponce : ZFS Administration, Part XVII- Best Practices and Caveats https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-124825 Fri, 19 Apr 2013 11:00:24 +0000 http://pthree.org/?p=2950#comment-124825 [...] Getting and Setting Properties [...]

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By: Aaron Toponce : ZFS Administration, Part V- Exporting and Importing zpools https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-124811 Fri, 19 Apr 2013 10:56:48 +0000 http://pthree.org/?p=2950#comment-124811 [...] Getting and Setting Properties [...]

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By: Aaron Toponce https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-124493 Wed, 20 Mar 2013 20:37:03 +0000 http://pthree.org/?p=2950#comment-124493 Yeah. I decided against zdb(8) last minute. Sorry about that.

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By: Michael https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-124490 Wed, 20 Mar 2013 19:56:30 +0000 http://pthree.org/?p=2950#comment-124490 Very nice. Just finished reading to the end. I didn't see the zdb post you mentioned at the end of this post (XVI). If you don't still plan to add a post on zdb at the end maybe delete the reference to zdb from the end of XVI.

Thanks again !

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By: Aaron Toponce : ZFS Administration, Part VIII- Zpool Best Practices and Caveats https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-123125 Mon, 14 Jan 2013 16:16:26 +0000 http://pthree.org/?p=2950#comment-123125 [...] Getting and Setting Properties [...]

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By: Sim https://pthree.org/2013/01/02/zfs-administration-part-xvi-getting-and-setting-properties/#comment-122573 Wed, 02 Jan 2013 16:51:38 +0000 http://pthree.org/?p=2950#comment-122573 A really excellent series of articles!

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