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Questions tagged [zfs]

ZFS is a modern file system and volume manager originally developed by Sun Microsystems and licensed under the CDDL. It is a copy-on-write file system with support for large storage arrays, protection against corruption, snapshots, clones, compression, deduplication and NFSv4 ACLs. An open-source fork of ZFS can be found at http://open-zfs.org/ , which is supported by ZFSonlinux.org, illumos.org and ZFS developers in the FreeBSD & Mac OS X communities.

ZFS is supported out of the box on a number of operating systems:

  • Solaris 10
  • Oracle Solaris 11 Express
  • FreeBSD
  • NexentaStor
  • illumos - specifically, illumos-based distributions, like:
    • Nexenta's illumian
    • Joyent's SmartOS (server OS with strong focus on virtualization)
    • OmniTI's OmniOS (general purpose server OS)
    • OpenIndiana (general purpose desktop/server OS)

Due to license incompatibilities, the CDDL licensed ZFS code cannot be distributed as part of the GPL licensed Linux kernel. Other alternatives methods are available for running ZFS on Linux:

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What are the different widely used RAID levels and when should I consider them?

This is a Canonical Question about RAID levels. What are: the RAID levels typically used (including the RAID-Z family)? deployments are they commonly found in? benefits and pitfalls of each?
MDMarra
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ZFS vs XFS

We're considering building a ~16TB storage server. At the moment, we're considering both ZFS and XFS as filesystem. What are the advantages, disadvantages? What do we have to look for? Is there a third, better option?
Tamas Czinege
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ZFS on FreeBSD: recovery from data corruption

I have several TBs of very valuable personal data in a zpool which I can not access due to data corruption. The pool was originally set up back in 2009 or so on a FreeBSD 7.2 system running inside a VMWare virtual machine on top of a Ubuntu 8.04…
ssc
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How to delete all but last [n] ZFS snapshots?

I'm currently snapshotting my ZFS-based NAS nightly and weekly, a process that has saved my ass a few times. However, while the creation of the snapshot is automatic (from cron), the deletion of old snapshots is still a manual task. Obviously…
growse
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Ext4 vs. XFS vs. Btrfs vs. ZFS for NAS

My use case: I have Ubuntu Server 18.04 installed on an M.2 SSD. I have a 4TB HDD I want to add as storage. Since it's mostly for large media files and backups, it won't be written to very often. Which filesystem do you think is best suited for this…
Alex Shaw
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I am going to chop the FreeBSD automounter into little pieces and boil them in oil

I am trying to expose a hierarchy of home directories to a number of FreeBSD jails. The home directories are configured such that each is a unique ZFS dataset. The jails are used for development work and hence are created and destroyed on a…
larsks
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Why are all the zpools named "tank"?

In practically every example of ZFS usage that I've seen online (including several questions here), the zpool is named "tank". Why? Is there some sort of significance to the name or is it just that the original documentation used "tank" so that's…
asciiphil
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Is bit rot on hard drives a real problem? What can be done about it?

A friend is talking with me about the problem of bit rot - bits on drives randomly flipping, corrupting data. Incredibly rare, but with enough time it could be a problem, and it's impossible to detect. The drive wouldn't consider it to be a bad…
scobi
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Delete 10M+ files from ZFS, effectively

I have written a buggy program that has accidentally created about 30M files under /tmp. (The bug was introduced some weeks ago, and it was creating a couple of subdirectories per second.) I could rename /tmp to /tmp2, and now I need to delete the…
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ZFS best practices with hardware RAID

If one happens to have some server-grade hardware at ones disposal, is it ever advisable to run ZFS on top of a hardware-based RAID1 or some such? Should one turn off the hardware-based RAID, and run ZFS on a mirror or a raidz zpool instead? With…
cnst
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LVM snapshots vs. file system snapshots

As far as I know, LVM makes it possible to take snapshots of a volume. There are also a number of file systems (ZFS, Btrfs, reiserfs, ...) which supports snapshots. However, I've never understood the difference between LVM snapshots and file system…
nip3o
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Clear a permanent ZFS error in a healthy pool

I scrubbed my pool today, and after the scrub finished, I noticed there was an error that corrupted a file. I didn't care about the file, so I deleted it. Unfortunately, the error remains (now referenced by a hex ID and not a filename), and I don't…
Kevin Wood
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How to perform incremental / continuous backups of zfs pool?

How can zfs pools be continuously/incrementally backed up offsite? I recognise the send/receive over ssh is one method however that involves having to manage snapshots manually. There are some tools I have found however most are no longer…
Greg
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Write speed requirement : 1.1GB/s possibilities?

We will have a machine at work, that on peak performance, should be able to push 50 ("write heads") x 75GB of data per hour. That's peak performance of ~1100MB/s write speed. To get that from the machine, it requires two 10GBi lines. My question is…
SvennD
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ZFS endless resilvering

I have a large (> 100TB) ZFS (FUSE) pool on Debian that lost two drives. As the drives failed, I replaced them with spares until I could schedule an outage and physically replace the bad disks. When I took the system down and replaced the drives,…
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