Questions tagged [zfsonlinux]
zfsonlinux provides a native Linux kernel port of the ZFS filesystem so that ZFS may run natively on Linux. It is very different from ZFS-fuse which provides ZFS on top of a userspace-filesystem layer. The ZFS On Linux project is hosted on zfsonlinux.org.
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ZFS on Linux disk replacement best practices
I have an 8-bay NAS running Fedora 29 (kernel version 4.20.8) and zfs version 0.7.12. All of the drive bays are used for a zfs pool named “tank.” Here is the zpool layout:
tank
mirror-0
sda
...
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/dev/zvol/pool/group/srv points to partition zd0p16 not volume zd0 - bug or feature?
I am only starting to get familiar with openzfs 2.2.0 on Linux (Ubuntu kernel 6.5) and immediately ran into something strange. A symlink I was expecting to point to a zvol block device.. was pointing ...
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Can ZFS send/receive help me recover from partial pool loss after upgrade to Ubuntu 22?
I have a long-running ZFS pool under Ubuntu, which has been through many upgrades. After upgrade from Ubuntu 20 to 22, the encrypted filesystems refuse to mount, though the rest seem OK. zpool ...
- 161
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zfs force import multiple VMS (IDs) and now can't find VM but it's not missing according to zfs?
I'm completely new to ZFS. Today, I did something stupid and caused a problem where I need to recover my entire OS. On a live OS I'm using to recover my machine, I need to mount my ZFS volumes for ...
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1
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What ZFS pool, vdev and dataset properties should most people use?
ZFS has many different configurable properties for pools, for vdevs and for datasets. Many of those can be changed at any point, but some can only be set at creation time (or only affect data written ...
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Why doesn't ZFS vdev removal work when any raidz devices are in the pool?
First: I'm perfectly okay with accepting that this is the case for now and am not looking for an immediate solution, rather I'm trying to understand the technical limitation for this constraint.
I'm ...
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Can I mirror a 2-disk striped zpool to a single large drive?
Currently I have a 4TB pool with two striped drives:
# zpool status
pool: lxd
state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
still be used, but some ...
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1
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182
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ZFS I/O Error, Kernel Panic during import
I'm running a raidz1-0 (RAID5) setup with 4 data 2TB SSDs.
During midnight, somehow 2 of my data disks experience some I/O error (from /var/log/messages).
When I investigated in the morning, the zpool ...
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2
answers
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How does zfs know which snapshots to send with the `-I` flag?
From the manual:
A group of incremental snapshots can be combined into one snapshot by
using the zfs send -I option. For example:
# zfs send -I pool/fs@snapA pool/fs@snapD > /snaps/fs@all-I
How ...
- 101
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Persistent ZFS pool errors on Ubuntu, even after repeated scrubs
My 3-disk ZFS pool has been scrubbed several times after replacing failing disks.
"zpool status -v" provided a list of files which were deleted and removed a good number of errors.
Despite ...
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1
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81
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Samba and ZFS resulting in NT_STATUS_BAD_NETWORK_NAME
I am currently trying to share my ZFS dataset using SMB. Unfortunately I receive the error NT_STATUS_BAD_NETWORK_NAME every time I try to connect to the share. The error does not make much sense to me ...
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ZFS on Hetzner Rescue fails with `checking whether inode_owner_or_capable() takes user_ns... configure: error:`
Normally, when booting into the Hetzner rescue system, using the 'zfs' command will automatically install zfs tooling inside the rescue system.
This is currently not working;
checking whether ...
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automatic mounting of encrypted zfs dataset
As a newbie to zfs, I am having trouble getting an encrypted dataset mounted during boot.
The dataset is protected with a raw key and not a passphrase.
This is how I created the zpool and the dataset:
...
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331
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zfs pool with slow speed on SAS drive with high latency
We have 3 servers in a gluster pool.
Each computer's spec is (Advance STOR-2 Gen 2 at OVH):
AMD Ryzen 7 Pro 3700 - 8c/16t - 3.6 GHz/4.4 GHz
6 x 14 TB disk (WD DC HC 530, using CMR technologies) ...
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How to explain that ZFS' snapshot reports 'WRITTEN' as 4.26GB, but the transfer size is actually 31.4GB?
When I run this query on a dataset
zfs list -d 1 -t all -o name,used,refer,written,compressratio sfg-backup/mx
I see the following stats:
zfs list -d 1 -t all -o name,used,refer,written,compressratio ...
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1
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364
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Forcefully forget / unmount ZFS pool after drives disconnected
First off, I made a mistake & I acknowledge that, but now I'm stuck with a "broken" ZFS driver and want to restore it without rebooting my machine.
How I can say ZFS on Linux to just ...
- 103
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Unexpected ZFS async write performance at different queue depths
For some reason, QD2 seems to be the best in terms of raw IOPS...
After seeing an interesting article comparing a couple different drives for SLOG usage, I got curious about the performance of my own ...
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ZFS pool disappears and says "I/O error" because of one missing device
I had a ZFS pool named data with 3 disks. Two disks were attached to the raidz by ID, but the third one was attached by volume (sda). I physically removed the sda device because I wanted to attach it ...
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ZFS send/receive fails, target has been modified, because of a zfs userspace query?
I use zfs send/receive to replicate a zfs file system to another server every day. The workflow is the standard send receive:
# 1. create snapshot on source
zfs snapshot ${source_fs}@${today}
# 2. ...
- 507
2
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3
answers
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How to nest & share multiple ZFS pools over Samba to multiple users
I have the following ZFS structure:
% sudo zfs list 16:03:46
NAME USED AVAIL REFER MOUNTPOINT
zpool1 ...
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0
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827
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Slow read speed in ZFS mirror (slower than write speed, and very slow for small chunk sizes)
I have a server running debian on top of a ZFS 3-way mirror of Exos X18 18TB (ST18000NM001J).
I'm benchmarking it and I'm finding some surprises for the read rate under certain conditions.
But first, ...
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338
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How ZFS avoids inodes' number exhaustion and why wasn't it implemented in previous filesystems (e.g. ext4)?
Chapter 1 of Oracle's ZFS Guide states that
all metadata is allocated dynamically, so no need exists to preallocate inodes
which was a positive surprise, but makes me wonder why the methods ZFS uses ...
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1
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ZFS: Replace raidz1-member of a striped pool for raidz2
I have a pool (in Ubuntu 20 LTS) like this:
# zpool status
pool: zpool_test
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
zpool_test ONLINE 0 ...
- 21
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0
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ZoL+FIO Randwrite nvme bs=8k@32io = 148MiB/s?
Sorry for the title, but it's very short summary of BS that I'm looking into. Situation
I'm using ZoL 2.1.5 (from jonathonf's ppa) on Ubuntu (tried 20.04&22.04)
I have following NVMe disk
...
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1
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How can I list what zfs compression algorithms are available?
I have a zfs pool on a production system and I would like to see if it's possible to use zstd compression instead of the current gzip setting.
Is there any way to list available compression options?
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ZFS size discrepency between 2 very similar configurations
I have 20X sata 12TB disks in a file server with a Broadcom/LSI MegaRAID SAS39xx raid controller. It’s running ubuntu. For an performance experiment, I created two storage pools:
-A single hardware ...
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458
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On Linux ZFS Server - What is eating my memory?
Our monitoring tool regularly reports low memory for one of our servers running ZFS.
# free -g
total used free shared buff/cache available
Mem: 125 ...
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1
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383
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ZFS disk with Postgresql fragmenting quickly with write-heavy application
I am running a write-heavy application where I am storing my Postgresql on ZFS. Generally, it works well, but I am finding that my ZFS pool is fragmenting heavily. I even created a new ZFS pool and ...
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zfs: flush cache without exporting
For testing I need zfs' cache to be cold.
I can flush caching from the pool by removing the cache disks, exporting and importing the pool. This gives the effect I want. But would really like not to ...
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Import a ZFS pool from a disk snapshot of another machine
I have a server on Azure with a disk mounted that contains a ZFS filesystem.
I also have a snapshot of the disk (taken from Azure, not zfs snapshot) which I want to mount to a new server.
The disk ...
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1
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Zpool permanent error for raidz2
Problem: Zpool shows "errors: Permanent errors have been detected in the following files: tank/vms/fileserver:<0x0>
Server has six 12Tb drives in a raidz2. These are spinning drives.
Zpool ...
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883
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Remove Missing Drives from ZFS Pool
After an embarrassing session trying to replace a disk in my ZFS pool, I have a bunch of entries representing disks that are no longer present in the system:
NAME STATE READ ...
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ZFS/ZoL: Consequences of increasing zfs_vdev_async_read_min_active (and max)?
Vdev async read queues have min=1 and max=3 by default. All sync read/write queues are defaulted to min=max=10, while async writes get min=2 and max=10.
Async reads are described as "prefetch ...
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255
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Multipass mount folder on zfs file system - Source path does not exist
I am trying to add storage to an existing Multipass VM. I created a new ZFS filesystem, mounted locally at /zfs/morespace. Then tried to mount it with
multipass mount /zfs/morespace existingvm:/mnt/...
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0
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324
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ZFS send/recv full snapshot
I have been backing up my ZFS pool in Server A to Server B (backup server) via zfs send/recv, and using daily incremental snapshots.
Due to hardware issues, the ZFS pool in Server A is now gone - and ...
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2
answers
653
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How can one recover/write a label (clone existing one)?
ZFS stores 4 labels, 2 at the beginning of a device, 2 at the end. When they are corrupted a pool cannot be mounted.
I had a case of 3 broken labels (failed to unpack), but 1 was still intact. I could ...
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2
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Limiting ARC Size for the proposed system
I have a pool of 5 x enterprise 12Gps SSD that I use for internal storage for a proxmox server. This pool is used to stand up VMs and containers.
The problem is that it is eating up a lot of my ...
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2
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Frozen boot due to slow disk/controller
Im running ubuntu 20.04 on dell r740xd, One of the disk controller seem to present the disk(multipath disks used for openzfs pool) slow while the server is booting. If the server is boot from '...
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ZFS disk error on write
our ZFS backup pool is producing strange disk errors when writing data. This pool is replicated via DRBD on a second server with identical hardware which is also experiencing the same errors. This is ...
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Recovering data from a zpool with a missing device
I have a zpool consisting of two mirrored drives, storing all my personal data. I wanted to add another mirror drive, since the other drives have been in use for several years now. Instead, I managed ...
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Does zfs zfs recv validate checksums?
It seems that zfs send includes a checksum for all included data (stated for instance here). Is this checksum automatically verified by zfs recv? I would assume it is, but I cannot find any ...
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ZFS datasets wont mount after upgrade to ubuntu 21.10
So i recently upgraded from Ubuntu 21.04 to 21.10 and now my ZFS datasets wont mount, even manually using the forced option.
I have tried exporting the pool and re-importing the pool, but even trying ...
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Does it make sense to create a zpool with lots of mirror vdevs?
To prefix, I am rather new to ZFS. My goal is to create an internal NAS system, with minimal chance of losing all my data.
I've currently acquired four 4TB disks, and I plan to run them in a single ...
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812
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Is there an advantage to using discreet ZFS datasets/filesystems in a single zpool?
I have a Centos server utilizing ZFS on Linux. The disks are in a single zpool. When you type in zfs list it shows a single filesystem(?)(dataset?), tank1.
NAME USED AVAIL REFER ...
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Erratic (terrible) Disk Performance I/O (Debian/Proxmox)
Summary
I'm seeing dramatically fluctuating I/O performance on a ZFS SSD mirror in Proxmox VE 7 (Bullseye). I'm simply too much of a novice to be able to track it down on my own.
Details
This is VERY ...
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.zfs folder's missing, but snapshots are still there and mountable (inode trouble?)
$ sudo zfs list -t snapshot | grep childDataset3
a whole bunch are listed as expected (e.g. pool/dataset/childDataset3@today)
$ ls /pool/dataset/childDataset3/.zfs
ls: cannot access '/pool/dataset/...
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ZFS Pool Disk faulted. Offlined and replaced and now I am stuck
Original fault:
pool: datastore7
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 ...
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1
answer
180
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ZFS Transfer extremely bursty
I am testing a new ZFS configuration with z-std for log storage and storage of highly compressible files.
The Array is tested on a 5 drive raidz-1 in a virtual machine on my PC which has direct access ...
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1
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Sequential write to zvol is much slower than to a dataset on the same zpool
While experimenting with Proxmox VE, we have encountered a strange performance problem:
VM disks can be stored (among other options) as individual raw ZFS zvols, or as qcow2 files on a single common ...
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Are ZFS snapshots really "free"?
I've heard many times that ZFS snapshots are "free", that because of ZFS' copy-on-write design snapshots do not consume any disk space unless data is changed, and only then the space usage ...
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