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Long night, a zfs and some questions after using zfs get all

I heard my main zfs pool is scrubbing again so i decided to take a look on it. If first started with refreshing my knowledge by using some zpool default commands.

zpool iostat 2 zpool status 2
Both upper commands displays important informations about your pool in an interval of 2 seconds. You can even add a "-v" if you want to know more ;-).

After watching the scrubbing for a while, i also remember the existence of some zfs attributes.

zfs get all
Et voilà, all attributes are listed very well.

I studied the attributes and was quite happy that i already configured a lot the right way. Compression was set to backup and tool, but not to image for e.g. The only thing i missed was the thing about the access time (atime). I really don't care about access time for my files, so it was time to disable this feature to gain some speed.

zfs set atime=off rpool

I was alos not shure if the following attributes are doing what i estimate of them.

sharenfs zoned snapdir utf8only normalization vscan nbmand sharesmb quota reservation

But after quickly asking the world wide web, i found a simple but usefull page called This page lists all available (ZFS v28) attributes and adds usefull informations to it.

I was also investigating the compression attribute. But after a while of surfing and testing on my own (by switching compression), i came to that point, that the default compression method (LZJB) is a good balancing act between speed and cpu usage.

While using my browsers, i also stumbled over old bookmarks i want so share. Best Practices Guide Evil Tuning Guide

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linux - EXT4 In kernel 3.5 Gets CRC32 Meta-Data

Posted by Michael Larabel on June 01, 2012 The pull request for the EXT4 file-system in the Linux 3.5 kernel and there's one prominent new feature. The EXT4 file-system with the Linuux 3.5 kernel will now support CRC32 check-sums on the meta-data fields. This work was done by Darrick J Wong to further improve the reliability of the EXT4 file-system. The EXT4 on-disk layout has changed to support the extended meta-data check-summing. Aside from this new feature, there's the usual list of bug-fixes and clean-ups. The EXT4 Linux 3.5 pull request can be viewed at

Cool, i never thought about the idea to extend the ext4 since zfs is the only way to go for my head ;-).

Don't get me wrong, it is no killerfeature but it is nice to read that ext4 gets extended.

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