Tag: zpool
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ZFS: zpool replace returns error: cannot replace, devices have different sector alignment
Trying to replace a failed SSD in a zpool we encountered the following error: cannot replace 4233944908106055 with ata-INTEL_SSDSC2BW240A4_CVD02KY2403GN: devices have different sector alignment The pool was aligned to 4k sectors – e.g. ashift=12 – whereas the new SSD was aligned to 512b sectors. There’s a quick and easy fix to this –…
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ZFS: Adding a new mirror to an existing ZFS pool
Mirrored vdevs are great for performance and it is quite straight-forward to add a mirrored vdev to an existing pool (presumably one with one or more similar vdevs already): zpool add [poolname] mirror [device01] [device02] [device03] If it’s a two-way mirror you will only have two devices in the above. An example…
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Western Digital Green drive resilver rates
We get asked fairly regularly about resilver rates for ZFS pools – these matter as it impacts on how quickly a vdev with faulty disks can rebuild data onto a fresh disk, as well as how quickly you can swap one disk for another. The longer it takes to rebuild the vdev after…
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How to add a drive to a ZFS mirror
Sometimes you may wish to expand a two-way mirror to a three-way mirror, or to make a basic single drive vdev into a mirror – to do this we use the zpool attach command. Simpy run: # zpool attach [poolname] [original drive to be mirrored] [new drive] An example: # zpool attach seleucus…
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ZFS Basics – zpool scrubbing
One of the most significant features of the ZFS filesystem is scrubbing. This is where the filesystem checks itself for errors and attempts to heal any errors that it finds. It’s generally a good idea to scrub consumer-grade drives once a week, and enterprise-grade drives once a month. How long the scrub takes depends…