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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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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ZFS RAID and LUKS encryption in Linux

I'm planning to setup a set of 3x 2TB 7200rpm drives as a LUKS-encrypted Z-RAID pool in Linux (for a NAS solution). My understanding of the problem at hand is that the only way to achieve this is to luksFormat every physical device and then…
MasterM
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If a RAID5 system experiences a URE during rebuild, is all the data lost?

I understand the argument regarding larger drives' increased likelihood of experiencing a URE during a rebuild, however I'm not sure what the actual implications are for this. This answer says that the entire rebuild fails, but does this mean that…
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Should I create ZFS zpools with whole disks or partitions?

I am making zpools on FreeBSD machine. While creating zpools I observe these two cases: If I take raw disks and create zpool then I am able to form zpools and they are working perfectly. If I format disks using gpart in freebsd-zfs format and then…
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ZFS performance: do I need to keep free space in a pool or a file system?

I know that the performance of ZFS heavily depends on the amount of free space: Keep pool space under 80% utilization to maintain pool performance. Currently, pool performance can degrade when a pool is very full and file systems are updated…
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Moving a ZFS filesystem from one pool to another

I am extending a Solaris 10 U8 server with an extra storage pool in addition to the root rpool. What is the most effective / simple / reliable way of moving particular ZFS filesystem(s) from rpool to this new storage pool? Can it be done online or…
Asgeir S. Nilsen
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ZFS - Is RAIDZ-1 really that bad?

I have an NAS server with 4x 2TB WD RE4-GP drives in a RAID10 configuration (4TB usable). I'm running out of space (<1TB usable space left). I have $0 to spend on bigger/more drives/enclosures. I like what I've read about the data-integrity features…
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How large is my ZFS dedupe table at the moment?

I have read a lot of information about planning RAM requirements forZFS deduplication. I've just upgraded my file server's RAM to support some very limited dedupe on ZFS zvols which I cannot use snapshots and clones on (as they're zvols formatted as…
Josh
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For L2ARC and ZIL: is it better to have one large SSD for both, or two smaller SSDs?

Main references ZFS L2ARC (Brendan Gregg) (2008-07-22) and ZFS and the Hybrid Storage Concept (Anatol Studler's Blog) (2008-11-11) include the following diagram: Question Should I interpret the vertical white line – at the SSDs layer – as a…
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ZFS Data Loss Scenarios

I'm looking toward building a largish ZFS Pool (150TB+), and I'd like to hear people experiences about data loss scenarios due to failed hardware, in particular, distinguishing between instances where just some data is lost vs. the whole filesystem…
Cyclone
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FreeBSD: How to know real file size on zfs with compression on?

I'm using zfs on my FreeBSD 9.0 x64 and pretty happy with it, but I find it hard to count directory real, not compressed, size. Surely I can walk over the directory and count every file size with ls, but I'd expect some extra key for du for that…
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Hosting a ZFS server as a virtual guest

I'm still new to ZFS. I've been using Nexenta but I'm thinking of switching to OpenIndiana or Solaris 11 Express. Right now, I'm at a point of considering virtualizing the ZFS server as a guest within either ESXi, Hyper-V or XenServer (I haven't…
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How can I add one disk to an existing raidz zpool?

I have an OpenSolaris server with a zpool backupz comprised of four SCSI drives: -bash-3.2# zpool status backupz pool: backupz state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM backupz ONLINE…
Josh
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ZFS Datasets dissappear on reboot

I have installed ZFS(0.6.5) in my Centos 7 and I have also created a zpool, everything works fine apart from the fact that my datasets disappear on reboot. I have been trying to debug this issue with the help of various online resources and blogs…
Vishnu Nair
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How does BTRFS compare to ZFS?

I am considering which OS and filesystem to use on some new servers I have and am considering either Free BSD with ZFS, or Linux with BTRFS. The programs I have run on both systems, so the only issue is reliability of the filesystems and…
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