Category / ZFS

ZFS quota

19 April, 2017

ZFS is loaded with useful features, just a while ago I took a peak at setting quotes. Using just a few commands you limit the amount  of storage a certain pool can take. First let’s check if there is no quota set : zfs get quota This would result in something like : # zfs […]

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ZFS replace a broken disk

28 March, 2017

After a reboot, I got greeted with this error : root@server:~# zpool status pool: rpool state: DEGRADED status: One or more devices could not be used because the label is missing or invalid. Sufficient replicas exist for the pool to continue functioning in a degraded state. action: Replace the device using ‘zpool replace’. see: http://zfsonlinux.org/msg/ZFS-8000-4J […]

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Create a ZFS mirror pool

8 March, 2017

I recently revived a “old” compute cluster. While its hardware was formidable back in the day, now it has been replaced with a younger version, which has more compute nodes. I wanted to create a data partition of two disks, normally I have a raid controller but on this server, there is none.  An open invitation for […]

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Install ZFS on Centos

17 February, 2017

Installing ZFS on Centos has been ironed out pretty much, so just follow along. There are three ways I know of to install ZFS on Centos. The two methods are recommended, as they use a repository, the last is just compiling from source, which I like, since I decide when its updated. (as kernel updates […]

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After the fairy dust has settled on Let’s Encrypt, allot of good solutions are out there to get a valid certificate using the ACME protocol (see client list). Most of the technique’s use webroot as verification technique, while this is fine for most websites, it has some downsides. For one, you need to adapt (let […]

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Tuning of ZFS module

31 January, 2017

Tuning of ZFS module The more difficult part of ZOL is the fact that there are plenty of tune able kernel module parameters, and hence ZFS can be used in many kinds of systems for many different reasons. (laptops, file-servers, database-servers, file-clusters) However some of the parameters come bad out of the box for file […]

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Basic ZFS tune tips

26 January, 2017

Lets start out with saying that ZFS on Linux (ZoL) is pretty awesome, snapshots, compression-on-the-fly, quota’s, … I love it. However ZoL also has issue’s, I even blogged about some in the past. (a full ZFS pool, failing to load ZFS module) Most cases where my own fault, but still, its very uncommon for a file system […]

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Snapshots in ZFS (ZOL)

22 January, 2017

One of the impressive tools in ZOL (ZFS On Linux) is snapshots. Snapshots are a way to make a ‘instant backup’ of the files on the system. The name backup, is not completely correct. If the system dies, the snapshots won’t save you, since snapshots are on the same storage as the data, they don’t eat […]

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Uh-oh, trying out zdb and finding this error, doesn’t breath confidence does it ? Here is how you can solve this minor issue : # zdb cannot open ‘/etc/zfs/zpool.cache’: No such file or directory Just set it as a value to the zpool : zpool set cachefile=/etc/zfs/zpool.cache poolname getting the pool name can be done using […]

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Starting the new year with : No space left on device I looked to the usual suspects (/tmp, /data, …)  but nothing excessive … It was my sanoid setup, woops! A gazillion snapshots ! For some reason one of my containers changes around ~300 Gb a day, and guess who keeps 60 days of snapshots, on […]

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