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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.

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26 views

What kind of metadata is primarily being loaded/evicted from ARC, in my ZFS system?

I'm trying to check how my ZFS pool's ARC is used, motivated by "do I need more RAM, even though expensive". I have 128GB fast ECC and using NVMe SSDs for L2ARC, but it's still doing a lot of small ...
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23 views

Storage setup for home servers [closed]

I'm looking to set up my first home server, for multiple purposes, with Proxmox. I already got the hint it's best to use 2 SSDs (of not too big size) for the actual Proxmox installation. As far as I ...
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1answer
42 views

Data missing in a degraded zfs pool

This is my first attempt to create a zfs pool manually under Proxmox. I have created a raidz2 zfs pool with 5 drives (4 WD RED 1TB NAS drives and 1 old 1TB Seagate). I also forgot to specify 2 spares,...
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0answers
161 views

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 ...
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1answer
42 views

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, ...
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35 views

ZFS drive is unavail after adding new drives to the computer

I have a server that I just recently redid, new drives, fresh OS (Ubuntu Server 18.04) I set up a new pool with the two new drives (4 tb each) with: zpool create poolname mirror /dev/sda /dev/sdb It ...
2
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1answer
87 views

Downsides of 8Kb cluster size for NTFS on top of ZVOL?

I am trying to maximize performance of Windows VM on a ZVOL. The official recommendation is that allocation unit size (volblocksize) on the zvol should be aligned with the allocation unit size of what ...
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1answer
76 views

Setting up zfs for multiple drives with redundancy on Ubuntu

Currently I have a Ubuntu server setup with 2 4tb disks each with ext4 in a RAID 1 (not using zfs). I want to have complete redundancy in case of a drive failure. I am adding another 2 4tb drives to ...
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1answer
50 views

ZFS magically vanishing available storage space

OK this is driving me nuts. Running zfs on a system, and my root partition has been shrinking with seeming no explanation. I have now run out of space and can't find where it all went. A simple df ...
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0answers
89 views

beginner issues with ZFS on OS X: how to re-mount?

I hope someone might be able to help me with this. I am using ZFS to create a 4 external hard drive raid system under OS X. I was able to set everything up and copy data to it. But then I think I made ...
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1answer
84 views

import zpool overwriting ownership/permissions (cf. -o uid=,gid=,umask= mount options)

I have a zpool from a system with different users than the machine I am working on that I want to copy data from. Therefore, I need to import and mount the zpool with read permissions. However, since ...
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35 views

what is the performance of zfs IO operations with unequal sized disks?

I have (ZOL) zfs pool (no mirror and raidz) named primaryPool # zfs list NAME USED AVAIL REFER MOUNTPOINT primaryPool 54.5G 41.9G 96K / primaryPool/ROOT ...
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139 views

How to decrypt, create, and mount LUKS encrypted zfs raidz pool at startup?

I have an Ubuntu-18.04 box running the OS off an SSD which I do NOT want to encrypt. I have 3 additional 2TB drives which I would like to use as encrypted (via LUKS) RAID-Z1 additional storage. I ...
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1answer
75 views

Move Linux tmp folders

I have Mint 19 installed on a fairly old machine, where the performance isnt great. I was able to move the swap partition to a ZFS pool with these instructions. However, I want to move the /tmp and /...
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1answer
196 views

Strategy for File System Permissions On KVM Shared Folder

I have a Ubuntu/KVM hypervisor environment that has access (via NFS) to ZFS data sets (aka file systems). I have been hosting the VM images on a ZFS file system which, although not the fastest thing ...
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1answer
171 views

How to create a linux container which inherits the hosts root file system, possibly with zfs?

What Hopefully the question in the title makes sense. I am wanting to create a low overhead (therefore no virtual machine) copy of the host operating system, with it running in a linux container. I ...
2
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1answer
172 views

Why is ZFS send/receive sending so much data across my LAN?

Just last weekend, I set up a new (clean install) backup server for my main FreeNAS machine, and started a manual complete pool backup between them. Both machines are enterprise hardware and run fast, ...
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0answers
38 views

Cluster storage server RAID configuration and specifications (Sanity check)

We are planning to buy a cluster for scientific computations, currently, we are in the process of putting together the specifications. We are not really sure, what should be the specifications of the ...
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1answer
49 views

Two Entangled ZFS Pools?

I am trying to clean up a mess on an Ubuntu 12.04 LTS server system using ZFS. Here's what zpool status shows: pool: TB2 state: UNAVAIL status: One or more devices could not be used because the ...
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0answers
48 views

Ubuntu with ZFS not able to boot

I have a server with 8 4TB HDDs, and I decided to try to manage it with ZFS on Ubuntu instead of with the RAID card built into the server. To do this I partitioned a disk in two, one for the ...
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0answers
168 views

Cannot import zfs volume

One of my disks died in a ZFS RAID system, and I have been trying to re-import the volume hoping the system will resilver after inserting a new drive, but no matter what zpool command I use, I always ...
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104 views

Practicality of Root on ZFS

I'm preparing to install a fresh OS on my desktop machine. Its basic specs are i7 3770S with 16GB Non-ECC RAM, which is the maximum that this board supports. I actually have XenServer on there now, ...
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1answer
240 views

how to use zdb or other zfs command to tell me what it is doing right now?

I keep seeing intermittent z_wr_iss kernel threads consuming all my CPU. I've no idea what ZFS is doing: maybe snapshotting, but why is taking so much CPU? It is not a cron job. I've read elsewhere (...
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1answer
288 views

ZFS scrub finds checksum errors, but badblocks and smartctl do not

I have configured a ZFS pool with two drives as a mirror. The operating system is Ubuntu 16.04 and I have been using the zfs 0.6.5 as packaged by the vendor. The drives are 3T WD Green and 3T WD Red (...
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1answer
47 views

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 ...
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1answer
144 views

Replacement drive failure during nas4free ZFS resilver

I'm running nas4free v. 10.3.0.3., using ZFS, with a four 2TB drive RaidZ1. Once a year, I do a complete backup, off-line the oldest drive, replace it with a new drive, and issue the "zpool replace ...
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1answer
512 views

ZFS RAID 10 pool with mixed disks size

I have 4 disks: 2x2TB and 2x1TB. All of the same RPM 7200 and manufacturer. OS is Ubuntu 16.04. I want to make a RAID 10 pool, but I've heard that mixing disks size is not a good approach to ZFS - ...
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2answers
185 views

Howto recover a raidz with 3 disk that faulted

I have a raidz vdev with 3 disks. Disk0 now failed and I try to recover, however I cannot run zpool import. Disk0 is still functional, however the partition table was corrupted and I tried to ...
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0answers
47 views

Is zfs suitable for this?

I have a little J1900 CPU server running debian linux with 8GB of ram and a 64GB SSD. I am using it to run a few very lightly loaded kvm virtual machines. It's not a very powerful server but demands ...
3
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1answer
466 views

Virtual Machine disk images on ZFS filesystem: a few questions

Background I use Ubuntu 16.04.4 LTS (converted to Server from Desktop) installed on a ZFS filesystem which itself is on an Samsung 840 Evo 120 GB SSD. I also have four HDDs which are two mirrors (1 ...
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291 views

Why is my ZFS pool spending 97% of its time reading the target and only about 3% writing, on a write operation?

This perplexes me and I don't know a way to drill down into what ZFS is actually doing. I'm using a clean install of FreeNAS 11.1 with a fast ZFS pool (imported mirrors on fast 7200s) plus a ...
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1answer
797 views

How to access a ZFS zvol SNAPSHOT block device?

I have an Ubuntu 16.04 box running ZFS. I'm using the zfs-auto-snapshot script to create regular snapshots. Included in my ZFS setup is a ZVOL block device. I want to access (read-only) a ...
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3answers
2k views

backup ZFS pool using rsync

I currently have a FreeNAS box for storing my personal files. I'd like to have an off-site backup, but I'm not willing to spend the money for a second computer capable of running ZFS properly. ...
5
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1answer
180 views

How to determine whether any of my ZFS snapshots are truly redundant and safe to delete without data loss?

I'm using FreeBSD 11.1 and the output of zfs list -t snap -r poolname shows a large number of my snapshots with "0" under "USED". I've read up on how ZFS accounts for space so I understand the basics, ...
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1answer
87 views

Partition missing in zpool import and blkid, but visible in gdisk

After a crash of my root btrfs I needed to force a shutdown with the power button. After re-installation of a root filesystem (independent from the ZFS pool I want to import) I no longer can import my ...
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1answer
246 views

Recommended zfs properties for blockchain data mountpoints

Blockchain based technologies require large datasets to work. It makes sense to put them on a separate volume/dataset in case the filesystem supports them. I'm using ZFS and was wondering whether ...
2
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1answer
374 views

How to create a GRUB boot CD to boot Debian with root on ZFS?

I installed Debian on ZFS following the following guide: https://github.com/zfsonlinux/zfs/wiki/Debian-Stretch-Root-on-ZFS I would like to avoid partitioning my hard disk and give ZFS the whole disk. ...
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1answer
235 views

ZFS snapshot behaviour handling of file modification, movement and rename

With ZFS being described as more like a database than a filesystem, it seems reasonable to expect it would behave a lot more like a version management system as well, intelligently managing file ...
4
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1answer
232 views

Externally attached ZFS pool hangs up, no sign of errors on drives

I have an array of 5 1TB WD Red drives in an external enclosure on a SATA multiplexer. This is being fed into a desktop machine with a SATA multiplexer controller. After about a year of service (this ...
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1answer
415 views

How to migrate a zfs pool with minimal downtime?

I have a RAID1 ZFS pool with 2x 5TB mirrored and 2x 1TB mirrored drives and want to replace the two 1TB devices with 4TB ones. Since zpool add is undoable[1], it's necessary to destory the pool after ...
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2answers
425 views

Can I use s SAS-expander without a dedicated hardware RAID Card?

I'm trying to expand my ZFS raid setup and I have used up all the available Sata-ports on my motherboard. I have read about SAS Expanders online and I think i have understood what they do. But one ...
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1answer
63 views

What is consuming ZFS pool space?

Environment: SP firmware 3.2.4.1 zfs Solaris 11 zones Problem: Poor system design has lead to constant space pressure on the internal disks. Once a pool goes over 80%, zfs goes into a whole lock ...
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1answer
238 views

How to create ZFS mirror with disks of different sector sizes?

Trying to repair a mirror in a ZFS pool: louis@watson:~$ sudo zpool status pool: watson state: ONLINE scan: resilvered 1.55T in 7h22m with 0 errors on Fri Oct 6 03:19:16 2017 config: NAME ...
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0answers
97 views

Backing Up Multiple Computers with ZFS [closed]

I'm planning out how to proceed with getting the storage of all my Debian PCs at home moved to ZFS. I previously considered this but the more I think about it, the more I wonder if it's going to limit ...
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1answer
196 views

Is there a ZFS-aware diff?

I often make snapshots of a ZFS volume (containing AOSP) make some changes (often extracting ZIP files over then top, or running scripts) and then run diff to see what has changed. This is really ...
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0answers
90 views

Multipurpose home server/NAS memory requirements

I'm building a NAS for my home & home office network. The NAS has 4TB of data on it (ZFS RAID1) and 8 gigs of ECC memory. The CPU is an E3-1230 v3. I'll be running Ubuntu 16.04 LTS on the ...
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1answer
602 views

Properties of ZFS ZVOL

I'm starting to teach myself how ZFS works - so I may have fundamental misunderstandings here - if so, please let me know. Is a ZVOL a block device, or does it simply behave in a manor similar to a ...
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1answer
283 views

zpool unavaliable after adding new disk to server (mount point changed)

I've a homeserver running Proxmox with two zpools. I want to replace a existing pool with smaller hdds by a new one. But when I plugin one of the two new SATA hdds, my zpools doesn't work. The logs ...
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2answers
459 views

Create a zfs raidz2 with 4k disks

I want to create a zfs raidz2 with 4 disks. I know this will "waste" at least 50% of the space but I aim at a high tolerance against disk failures. Using 5 disks for raidz2 is not recommended and 6 ...
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3answers
8k views

Does Git prevent data degradation

I read that ZFS and Btrfs use checksums to prevent data degradation and I read that Git has integrity through hashing essentially everything with each commit. I was going to use a Git server on a ...