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.

learn more… | top users | synonyms

4
votes
2answers
134 views

ZFS checksum errors, when do I replace the drive?

I'm fairly new to ZFS and I have a simple mirrored storage pool setup with 8 drives. After a few weeks of running, one drive seemed to generate a lot of errors, so I replaced it. A few more weeks go ...
3
votes
1answer
114 views

ZFS: good read but poor write speeds

I'm in charge of downloading and processing large amounts of financial data. Each trading day, we have to add around 100GB. To handle this amount of data, we rent a virtual server (3 cores, 12 GB ram)...
0
votes
0answers
14 views

Linux Ubuntu 16.04.1 UFS: Warnings in Dmsg and Console. ZFS

Why am I getting these warnings on my ZFS disks? ALl disks but sda are ZFS I'm guessing its nothing to worry about though. OS: Ubuntu 16.04.1 LTS, no external PPAs or repos Whole DMesg Warning ...
0
votes
1answer
42 views

ZFS: ARC and buffer cache with PostgreSQL

I am using Ubuntu Xenial, zfs and PostgreSQL 9.5 with all updates available atm. All testing is done on EC2 m4.xlarge (8GB RAM) and table size ~4GB. PostgreSQL effective_cache_size=6GB. First ...
3
votes
1answer
1k views

Linux ZFS does not buffer writes to write buffer (SLOG/ZIL)?

When experiencing write I/O, the log column in zpool iostat -v does not show any ZIL activity, ever. This results in higher than expected wait times when writing data to disk (sometimes over 80ms ...
4
votes
2answers
45 views

ZFS L2ARC for Mirror Pool

I was reading up on L2ARC for my ZFS. I currently have two Pools, One for Data, and the other for Linux Containers and Virtual Machines. I would like some help with L2ARC, I know how to add it but was ...
1
vote
1answer
86 views

Ubuntu 16.04 LTS with ZFS hanging on boot

Ubuntu 16.04 LTS host won't come back up after maintenance reboot. Seems to hang when it tries to bring up ZFS. Last message in the console is: Starting import ZFS pools by cache file... VERIFY(rs ==...
0
votes
0answers
28 views

Best practice for setuid and setgid in /root and user directories

ZFS allows to created datasets with setuid turned off, which (AFAIK) means that setuid bit can't be set on files stored in those datasets. Assume now that there are two datasets, one for the /root ...
2
votes
2answers
2k views

ZFS - Recover or repair a corrupted file in a snapshot from backup?

A pool has suffered permanent data corruption to file data that's part of a snapshot. If the file data was part of the filesystem (and not part of any snapshot), I could simply recover the file from a ...
2
votes
2answers
89 views

How do I configure Ubuntu 16.04 to show my ZFS zvols internal partitions?

I seem to be missing some zvol functionality, but I'm not sure how to phrase it. I had this functionality with these same zpools on an ArchLinux installation. (Migrated the server.) Ubuntu puts the ...
1
vote
0answers
27 views

ZFS issue after enlarging image

I created a new img using the following command: truncate -s 250G disk.img and I replace the existing image that I used for zpool with that one using (lxd.img was 2G): zpool replace lxd lxd.img ...
2
votes
2answers
50 views

Will ZFS automatically switch to fault tolerant when I add a third drive?

If I start off with a 2 drive stripped ZFS POOL will it automatically become a fault tolerant POOLS like RAID-5 when I add the third drive? I can't seem to find anything in the ZFS CheatSheets I find ...
0
votes
0answers
25 views

ZFS Snapshot showing unreachable inside snapdir

I am using ZFS with Linux 3.19.0-58-generic. I have created some snapshots, but when I cd into these directories after one point it becomes unreachable, what does that mean ? Is there any workaround ...
5
votes
1answer
76 views

Is the size reported by `zfs send` exact or estimated?

Consider the following command and the output: zfs send -Pvi \ tank/vms/langara@zfsnap-2016-05-11_00.00.00--1w \ tank/vms/langara@zfsnap-2016-05-13_00.00.00--1w \ | dd > /dev/null ...
5
votes
4answers
3k views

MongoDB and ZFS bad performance: disk always busy with reads while doing only writes

I have huge performance issues using MongoDB (i believe it is mmapped DB) with ZFSonlinux. Our Mongodb is almost only writes. On replicas without ZFS, disk is completely busy for ~5s spikes, when app ...
1
vote
0answers
21 views

Does zfs send scrub the sent data?

To my knowledge ZFS as a filesystem checks for data errors during each access to the data. I would therefore assume that it actually performs something like a scrub before sending the data thereby ...
1
vote
1answer
268 views

How do I upgrade and keep my ZFS pools on Ubuntu Server?

I have a server running the 4-year-old Ubuntu 12.04 LTS with zfsonlinux installed on the machine with a 1.5TB mirrored drive setup. The Ubuntu 16.04 LTS has no upgrade path, so I'll have to reimage ...
18
votes
7answers
4k views

Which filesystem for large LVM of disks (8 TB)?

I have a Linux server with many 2 TB disks, all currently in a LVM resulting in about 10 TB of space. I use all this space on an ext4 partition, and currently have about 8,8 TB of data. Problem is, I ...
3
votes
1answer
634 views

Why isn't my ZFS pool expanding using ZFS on Linux?

I have a ZFS zpool on linux under kernel 2.6.32-431.11.2.el6.x86_64 which has a single vdev. The vdev is a SAN device. I expanded the size of the SAN, and despite the zpool having autoexpand set to on,...
9
votes
2answers
689 views

Why is ZFS on Linux unable to fully utilize 8x SSDs on AWS i2.8xlarge instance?

I'm completely new to ZFS, so to start with I thought I'd do some simple benchmarks on it to get a feel for how it behaves. I wanted to push the limits of its performance so I provisioned an Amazon ...
1
vote
1answer
61 views

How to import a child of a broken zpool mirror on a different host?

I have a hard disk lying around which once belonged to a 3-disk ZFS mirrored pool on a Ubuntu 12.04 server, called d510. The disk was properly detached but its filesystem tank0 was not exported. I ...
3
votes
1answer
133 views

ZFS on Centos - “No such pool or dataset” and “devices is currently unavailable”

I'm trying to create zpools on CentOS 7 (3.10.0-327.10.1), and the zpool command seems to hate "wwn-0x" IDs. "zpool status" is clear - there are no zpools currently configured on the machine. I have ...
8
votes
3answers
4k views

Encryption with ZFS on linux

Does ZFS on Linux already support Encryption? If not, is it planned? I found tons of info for ZFS+LUKS but that's absolutely uninteresting: I want ZFS encryption so that I can do replication using ...
1
vote
0answers
40 views

Why ZFS ARC hit rate is higher than real performance hit?

We've got Debian Wheezy host with ZFS on Linux with in. It is used only for serving large files over http. User activity is mostly characterized by a lot of random read. We've noticed that ~95% ARC ...
0
votes
1answer
176 views

zfs: dataset does not exist

I'm not able to set mountpoint to the pool. # zpool import pool: wd-black id: 18120690490361195109 state: ONLINE action: The pool can be imported using its name or numeric identifier. ...
1
vote
0answers
140 views

ZFS copy on write

I am planning to use ZFS for backups. 5-10 servers will "stream" updates via DRBD to very large files (500 gigabytes each) on ZFS file system. The servers will generate about 20 megabytes per ...
1
vote
0answers
80 views

Mount ZFS dataset in unprivileged container

First a bit of information about my configuration: Ubuntu 15.10 ZFS pool created LXC containers stored in pool/lxc Dataset created in pool/mydataset owned by user1 Now I need one of the containers ...
7
votes
1answer
227 views

Extreme ZFS slowdowns after several months

I've got a general-purpose server, providing mail, DNS, web, databases, and some other services for a number of users. It's got a Xeon E3-1275 at 3.40 GHz, 16 GB ECC RAM. Running Linux kernel 4.2.3, ...
1
vote
2answers
85 views

Does the max-80%-use target suggested for ZFS for performance reasons apply to SSD-backed pools?

The Solaris ZFS Best Practices Guide recommends keeping ZFS pool utilization below 80% for best performance: Keep pool space under 80% utilization to maintain pool performance. Currently, pool ...
3
votes
1answer
116 views

Broken ACLs when “zfs send”ing a snapshot from a Linux machine to Solaris

I'm running ZFS on a Ubuntu machine that hosts our home directories. The pool has the following ACL setting: # zfs get all homes | grep acl homes aclinherit restricted default ...
0
votes
0answers
28 views

zfs Disk in pool accidentally pulled now shows pool degraded

I have a pool with 10 disks and we accidentally pulled the wrong disk and now the pool shows degraded, and suggests using zpool recover. Can we just "zpool scrub sdbe" to get the disk resilvered and ...
6
votes
1answer
66 views

ZFS keeps faulting the same device

Our storage server has some problems, just ago we had a broken disk (WD 4TB RE SAS), though the raidcontroller (LSI MegaRAID 9271-8i) kept the disk online (status : ok). Only Media error showed 1 ...
1
vote
2answers
279 views

zpool forgot all data devices of a pool: how to bring them online again?

My Debian server is running ZFS on Linux. Today I had to reboot it two times due to software upgrades. A first reboot because of ZFS update from some 0.6.4-1.2-1-wheezy to 0.6.5.2-2-wheezy, which went ...
1
vote
1answer
152 views

Access iSCSI block device, setup as ZFS volume on CentOS7 - won't automount on boot, hangs on reboot

I am running CentOS7 on a virtual instance at Softlayer. There is a block storage device available to the instance via multipath/iscsi I have successfully had this block device mounted as XFS. I ...
7
votes
3answers
1k views

Upgraded Ubuntu, all drives in one zpool marked unavailable

I just upgraded Ubuntu 14.04, and I had two ZFS pools on the server. There was some minor issue with me fighting with the ZFS driver and the kernel version, but that's worked out now. One pool came ...
1
vote
1answer
2k views

How to migrate a regular LXC container to a Proxmox LXC container?

How do you migrate a regular LXC container (from another or the same server) to a Proxmox LXC container, which can be accessed via the Proxmox web GUI? For example, I have a container created by ...
0
votes
1answer
88 views

How do I prevent ntfs-3g use starving my ZFS ARC of memory?

I have an HP Microserver running OpenMediaVault 2.1.18 (Stone burner), based on Debian GNU/Linux 7 (wheezy). A few days ago, I needed to copy a large number of files from a USB drive, formatted with ...
0
votes
1answer
364 views

ZFS on Linux - Debian - sharenfs datasets - can't write, only read

Short version: mounted datasets are RO, even though I'm trying to make them RW. Long version: we currently have a working implementation of ZFS on Linux on Wheezy (which I inherited when the ...
2
votes
0answers
38 views

Grow ZFS pool to use the whole disk

What's the (if there's any) way to grow a zfs pool that only uses a disk partially to use the whole disk? Background is, zfs is used here on a virtual machine and the Virtual machines disk has been ...
1
vote
1answer
128 views

zfsonlinux, raidz1: two disk corruptions: How I can use dd/dd_rescue and deceive zpool?

I have zfsonlinux (Centos 7), and raidz1. And I have trouble: two disks are dying. The first disk have Raw_Read_Error_Rate failure in SMART and Reallocated_Sector_Ct error (the disk has run out of ...
3
votes
2answers
1k views

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 ...
8
votes
4answers
12k views

Why isn't the arc_max setting honoured on ZFS on Linux?

I'm running ZoL 0.6.2 from their PPA on Ubuntu 12.04. It's on a host with 16GB of memory intended to run some VMs using KVM/Libvirt. After some time ZoL is using an insane amount of memory, reaching ...
1
vote
1answer
191 views

ZFS snapshot send incremental

I have been happily using zfsnap with CentOS and ZFSonLinux in a scripted manner similar to how it is described on the web site, but have run into an issue. Unfortunately backups did not run a few ...
3
votes
1answer
58 views

why are zfs on linux transfer rtates reported incorrectly after expanding array?

I have upgraded the drives in a 4 drive Raidz array in a NAS server and the array has auto expanded to the new size. In testing transfer rates from the NAS server now I observe that when performing ...
2
votes
2answers
177 views

Multiple RAID types on a ZFS pool

Reading the Ubuntu Wiki page on ZFS (https://wiki.ubuntu.com/ZFS) I found some claimed abilities of ZFS which I am not able to find any documentation of. If the claims are infact possible I would love ...
1
vote
1answer
113 views

Move ZFS filesystem (including snapshots) from one pool to another

I work with a setup where we use ZFS snapshots to maintain a historical record. We have a need to migrate this data from one ZFS pool to another. This question (Moving a ZFS filesystem from one pool ...
2
votes
1answer
215 views

Advice for building production 140 disk (420 TB) ZFS zpool [closed]

I have been tasked to build a large zpool for a data recording system. Using ZFS on Linux (0.6.4.2), on CentOS 6.5. Hardware specs: DL380 Gen8 80 GB ram 2x HP HBA H221 2x HP D6000, each with 70x ...
2
votes
2answers
472 views

ZFS - zpool replace never finishes

I have a 5 x 3TB raidz1 array on a ubuntu 14.04.1 server. Last month, one of the drives died (audible clicking). I was able to replace the drive with zpool replace RAID <dead drive> <new ...
1
vote
1answer
232 views

How can I directly read data from a file in Linux without using the filesystem cache?

I have shared storage which is mounted (read-only) on SERVER1, and mounted (read-write) on SERVER2. SERVER2 is writing data to a file. SERVER1 is reading data from that file. The file poling is <...
1
vote
1answer
164 views

ZFS estimated send size much larger than total data size

From zfs send -R -v pool/fs@snap: send from @ to pool/fs@snap estimated size is 6.50T ...but from zpool list: NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT pool 3.62T 2.36T 1.27T ...