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Questions tagged [zfs]

An advanced file system that can span multiple disks, heal itself from data corruption, deduplicate data, encrypt, etc.

ZFS is both a and a that supports

  • various layouts,
  • checksumming data to detect and repair corruption,
  • transparent compression,
  • copy-on-write snapshots and clones,
  • block device datasets (ZVOLs),
  • sending and receiving data streams,
  • resilvering only missing data rather than resyncing an entire RAID device,
  • dynamic striping, and
  • data deduplication.

ZFS was originally developed by Sun Microsystems, but in 2010, Oracle Corporation closed the source, which caused ZFS to fork into Oracle's closed-source branch and OpenZFS.

is a similar file system developed for .
Apple File System (APFS) is a similar file system developed by Apple.
Resilient File System (ReFS) is a similar file system developed by Microsoft.

407 questions
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How can I access the contents of a ZFS snapshot without affecting its current data?

I have a ZFS dataset which gets hourly snapshots taken. Yesterday, a change was made to some of the files which needs to be reverted; however, the dataset has ongoing changes which shouldn't be reverted. What are my options to access the snapshot…
STW
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Can two seperate zpools exist on the same physical devices?

Short: Can I share a disk between two separate zpools? Long: I want a raidz2 array but I can't afford it all at once. My possible solution is to start with two drives. I would create a mirror using only half the capacity of each disk. When I can…
Alex
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zpool import with missing cache device

Was going to try SmartOS, partially because I was not satisfied with FreeNAS for my usage. Created new zpool on old cache drive for SmartOS zones. That was all just backstory. The point is that now can't import the old FreeNAS pool on Ubuntu 15.04. …
user148509
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can zfs use mixed vdev mirror sizes?

can zfs do the following? 10 x 3TB disks as 5 mirrored vdevs plus 2 x 2TB as a mirror vdev. I am looking to use those two 2TB disks that I have for a total of 17TB, and then upgrade down the track. For example, could I later upgrade those 2x 2TB…
jakethedog
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Growing a ZFS pool from populated ext4 disks

I've got an Ubuntu media server with 4 ext4 2TB drives, 1 ext4 4TB drive, and 1 new blank 4TB drive. The ext4 volumes are configured as individual drives (not RAID, etc.). The 2TB drives are about 70% full and the 4TB drive is about 50% full. I'd…
Fred Hamilton
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How to zfs send an entire filesystem

I am trying to copy an entire filesystem between 2 machines. Based on documentation -R on zfs send should "Generate a replication stream package, which will replicate the specified file system, and all descendent file systems, up to the named…
HubertNNN
  • 413
3
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Can a zfs mirror contain combined disks?

Can I create a single zfs mirror by combining disks? mypool mirror1 disk1 (2TB) disk2 (2TB) combined disk3 (1TB) disk4 (1TB) In other words disk3 and disk4 should contain the same data as…
John Smith
  • 153
3
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1 answer

zpool import order in /dev/disk/by-id

If I have a disk: sdi, and there are three entries of it in /dev/disk/by-id: scsi-SATA_WDC_WD6001FSYZ-_WD-WXB1HB4SFS7W -> ../../sdi ata-WDC_WD6001FSYZ-01SS7B0_WD-WXB1HB4SFS7W -> ../../sdi wwn-0x50014ee004032d28 -> ../../sdi Now I use zpool import…
黃健瑋
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How do I remove old ZFS snapshots

After running updates on Ubuntu I receive a warning about my ZFS filesystem. Is there a utility or script I can use to remove old snapshots? Below is the message: ERROR couldn't save system state: Minimum free space to take a snapshot and preserve…
Daniel
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Rename zfs disk path

FreeBSD zfs 2 disk mirror I replaced a dead hdd and somehow it renamed ada0 to ada1 zpool status mirror-0 DEGRADED 0 0 0 ada1p3 ONLINE 0 0 0 13232760139244878088 UNAVAIL…
Tony
  • 31
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A clear explanation of metaslab groups and gangs, in ZFS?

I'm trying to troubleshoot a problem related to metaslab and spacemaps in ZFS on FreeBSD, for which I'd like to have a clear understanding of how these work. Most of the docs make sense. But I keep coming across gangs, and groups, and the…
Stilez
  • 1,695
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1 answer

Are ZFS's ARC counters persistent?

Suppose I have some data that is accessed frequently and some less-frequently accessed data. I understand that the ARC will eventually learn to stop evicting the frequently-accessed data to make room for other data just because the other data was…
lungj
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ZFS and mixed drives sizes for a mirrored stripe array

I'm having a performance problem with my ZFS array that i think to be due to defragmentation. I have a striped array of 20 devices with 2 mirrored drives each. I've recently added some devices to this striped array that are bigger (2x) than the…
Mara Ara
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How does zfs promote work and what are the consequences of using it

I know that zfs promote swaps a clone with the master, but other than that the documentation does not mention anything. What consequences have promoting a dataset? Can I just promote them back and forth any time I need to delete one, or will it be a…
HubertNNN
  • 413
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Can ZFS sync=disabled cause corruption of previously written data?

If sync=disabled is set, I understand that the ZIL isn't written to disk and, instead, changes are written directly to disk. Aside from possibly inconsistent data from an application-standpoint due, especially in networked situations where data that…
lungj
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