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 ...

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1answer
90 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)...
2
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1answer
35 views

Adding more mirrored vdevs to a ZFS pool on Ubuntu

I'm on Ubuntu 16.04.1 LTS and I have a ZFS pool named unas containing two mirrored drives. I have now attached two more drives and I want to add these new drives to my unas pool as a pair of mirrored ...
0
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1answer
41 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 ...
4
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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 ...
4
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2answers
122 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 ...
2
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2answers
23 views

Delete ZFS filesystem with snapshots but no other children?

You can delete a ZFS filesystem (or other dataset) with zfs destroy <dataset>. That fails if the dataset has children, including snapshots. zfs destroy -r <dataset> will remove the ...
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0answers
29 views

ZFS restarts resilvering over and over again. Also very slow

Here's one of my Solaris 10 servers after a couple of disk replacements in a zpool pool: volume state: ONLINE status: One or more devices is currently being resilvered. The pool will ...
4
votes
2answers
190 views

Priming a ZFS L2ARC cache on Solaris 11.3

Is there a good way to prime a ZFS L2ARC cache on Solaris 11.3? The L2ARC is designed to ignore blocks that have been read sequentially from a file. This makes sense for ongoing operation but makes ...
2
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0answers
44 views

ZFS on linux with centos 7.2 sync reads slow to crawl when executing sync writes

We are running ZFS on linux with centos 7.2. The array has 26 6tb Seagate sas drives in a mirrored configuration and then stripped across the mirrors to form our pool. 128gb arc, 480GB l2arc PCI ...
2
votes
1answer
34 views

zfs mountpoint not using the dataset

I am currently building a media server based on Linux Mint. The OS is installed on a small SSD and the intention is to store the media files on two HDDs (2TB + 4TB). To this end I have created a zfs ...
1
vote
1answer
81 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 ==...
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17 views

Best topology for mirrored data servers in GlusterFS

I am currently laying out the topology for a GlusterFS cluster, which is expected to grow pretty fast. Therefore, scalability and resiliency are key in this regard. The topology I've come up with is ...
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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 ...
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52 views

How to enable space reclamation from KVM guest to ZFS zvol iSCSI target?

I have a ZFS volume "tank/kvm/webhosting", exposed through iSCSI (using tgt) to KVM guest. <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native' ...
2
votes
2answers
88 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 ...
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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
1answer
60 views

Recover ZFS deleted file names [closed]

I have to work on server with ZFS file system to recover deleted file names or recover actual files. I have very basic knowledge about ZFS and couldn't find easy way to achieve this. I just wonder if ...
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 ...
1
vote
1answer
187 views

zpool showing more storage than it should

I just expanded my zpool named storage with 3 HGST 6TB drives in raidz1. I thought this would add only about 11.x TB of storage (since they are really 6000GB drives) how ever now zpool list shows I ...
2
votes
1answer
53 views

ZFS - Solaris 10 doesn't see disks after reboot on HP Pro DL380 G7

The current box has 2 logical drives, shown in P410i Array Controller (F8 during POST) as: Logical Drive 1 - 2 SAS 72GB HD Raid10 <----root pool disk Logical Drive 2 - 4 SAS 146GB HD Raid 5 <-...
2
votes
2answers
91 views

JBOD server for ZFS without dedicated boot drive

I am looking at buying a cost-effective machine for using openAttic, which is simply Ubuntu 14.04 64bit with ZFS. The server I am looking at gives me 8 bays of 3.5", where I plan to put SAS 7.2k ...
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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
75 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 ...
2
votes
1answer
74 views

is it possible to convert dataset to sparse volume (thin provisioning)?

I've created ZFS datasets and installed virtual servers into them. Suddenly my ZFS volume free space is gone, but not all space is used in each dataset. I want to introduce thin provisioning (use ZFS ...
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0answers
42 views

ZFS mirror migrated to other system with dd -> zpool import fails

I'm pretty new to ZFS and this might be an easy problem (but I don't find any discussions about how to do this): I've messed up a FreeBSD installation on a Root-on-ZFS mirrored ZFS Pool on a ...
1
vote
1answer
53 views

ZFS Send Script works when run manually but not in Cron (Already tried common solutions)

Script on sending end is as follows: #!/bin/sh #Variables bigdata=vid-zfs-live/bigdata today=`gdate +%m-%d-%y` yesterday=`gdate -d'yesterday' +%m-%d-%y` #Actions zfs snapshot -r "$bigdata"@"$...
0
votes
2answers
35 views

Can the type of a previously created ZFS pool be changed?

I have a 2-drive zfs pool created in mirror mode. Now I've managed to get my hands on a third drive, and I was wondering if I could add the drive, and change the pool type to raidz, which is pretty ...
1
vote
1answer
169 views

Can ZFS snapshots on a NAS (accessed via Windows Previous Versions) be made more flexible in regard to renaming files?

I have a NAS running on OpenSolaris/illumos/OmniOS with several shared ZFS file systems where autosnaps are active to preserve a history (keep 4 15-minute snaps, 24 hourly snaps, 7 daily snaps and so ...
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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
47 views

zfs for Hadoop cloud instead of ext4 [closed]

Right now I have couple of linodes with ext4. I have a hadoop setup. What benefit would I get if I migrate my file system from ext4 to zfs. Will there be any benefit in response times? Any speed ...
1
vote
1answer
261 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 ...
1
vote
1answer
43 views

How to avoid loosing changes on the root filesystem when kernel upgrading?

On Solaris and variants, it makes a zfs clone of the current / filesystem and installs the new kernel there. When rebooting you get the new /. In my case I have a /scripts directory, so if I ever ...
2
votes
1answer
83 views

zfs convert linear to raidz5 or rebuild

Can i convert my linear span to a raidz-5? I finally have enough hard drives, and dont really want to thrash them about refilling with the backup data that they need to be holding. so currently, ...
3
votes
2answers
107 views

ZFS scrub load average is ridiculously high

I have a relatively new box here running Ubuntu with ZFS-on-Linux across an 18-disk array. The first couple of times I did a zpool scrub, it seemed like everything worked nicely, but the last several ...
0
votes
2answers
59 views

Does zfs recordsize impact compressratio

We host a postgresql95 OLAP database on zfs with lz4 compression turned on. As recommended we tuned the zfs recordsize to 8KB since this is postgres block size. The write ahead log is on it's own ...
0
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0answers
80 views

ZFS tuning for SSD queue depths

When using SSD on ZFS, what is the best configuration for the vfs.zfs.vdev.max_active parameters? As I know the default of this parameters is 1000, I don't have the intention to change this, but these ...
4
votes
2answers
181 views

Windows user can overwrite NFSv4/Solaris ACL permissions of files on CIFS/SMB share (grant himself full access), how do I prevent this?

I have SMB/CIFS file sharing set up on an OmniOS server with the Solaris kernel module which uses NFSv4 ACLs that should work correctly with Windows clients. I want to create a shared directory with ...
9
votes
2answers
683 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 ...
3
votes
1answer
132 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 ...
1
vote
1answer
57 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 ...
2
votes
1answer
157 views

Where is my ZFS SMB share?

We run this pair of OpenSolaris servers that provide file storage. They run active/passive and stay in sync via snapshot replication every minute or so. Originally, they both ran OpenIndiana, but ...
2
votes
1answer
48 views

Foreign cards in a HP server, do they cause the server to operate outside of specs?

I have a Proliant DL380 G7 I am going to be staging as lab server. As part of the server I plan to run ZFS as the base filesystem and installed 2 LSI 9211-8i cards for the disk controllers since the ...
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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 ...
2
votes
2answers
78 views

ZFS: very big files + compression + snapshots

I backup several virtual disks (total = around 4 Tb), with several weeks of retention time. I use 4 x 4 Tb disks in the computer dedicated to primary backup. The filesystem is ZFS RAIDZ2, so 8 Tb ...
1
vote
1answer
54 views

zfs zpool degraded drive missing

I have a degraded zpool called storage of 4 6TB Drives in 2 mirrors. One of the drives on the second mirror is unavailable. All cables seem to to be plugged in physically. Did my device id change? ...
0
votes
1answer
317 views

Why is zfs/btrfs recommended for an lxd host?

Note that for maximum performance, it's recommended to have /var/lib/lxd on a btrfs filesystem or setup ZFS or LVM and configure LXD to use a ZFS pool or LVM VG. Source Why is that? I.e. How ...
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0answers
166 views

ZFSonLinux : process stuck in D state, iowait for CPU 100%, HDD idle

I have a problem that occurs regularly,cca every 5 seconds. the rtorrent process gets stuck on disk wait D state for approx. 1-2 seconds,then continues with full speed. Sometimes the hangs take ...
0
votes
1answer
173 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. ...
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0answers
139 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 ...
3
votes
1answer
188 views

Ubuntu 14.04 blk_update_request I/O error on same sector across all drives with ZFS

I'm running Ubuntu 14.04 with ZOL version v0.6.5.4: root@box ~# dmesg | egrep "SPL|ZFS" [ 34.430404] SPL: Loaded module v0.6.5.4-1~trusty [ 34.475743] ZFS: Loaded module v0.6.5.4-1~trusty, ZFS ...