Questions tagged [zfs]

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 fork of ZFS can be found at http://open-zfs.org/ , which is supported by ZFSonlinux.org, illumos.org and ZFS developers in the FreeBSD & Mac OS X communities.

Filter by
Sorted by
Tagged with
186
votes
2answers
43k views

What are the different widely used RAID levels and when should I consider them?

This is a Canonical Question about RAID levels. What are: the RAID levels typically used (including the RAID-Z family)? deployments are they commonly found in? benefits and pitfalls of each?
68
votes
12answers
60k views

ZFS vs XFS

We're considering building a ~16TB storage server. At the moment, we're considering both ZFS and XFS as filesystem. What are the advantages, disadvantages? What do we have to look for? Is there a ...
46
votes
6answers
12k views

ZFS on FreeBSD: recovery from data corruption

I have several TBs of very valuable personal data in a zpool which I can not access due to data corruption. The pool was originally set up back in 2009 or so on a FreeBSD 7.2 system running inside a ...
40
votes
1answer
2k views

I am going to chop the FreeBSD automounter into little pieces and boil them in oil

I am trying to expose a hierarchy of home directories to a number of FreeBSD jails. The home directories are configured such that each is a unique ZFS dataset. The jails are used for development ...
37
votes
2answers
9k views

Why are all the zpools named “tank”?

In practically every example of ZFS usage that I've seen online (including several questions here), the zpool is named "tank". Why? Is there some sort of significance to the name or is it just that ...
33
votes
4answers
13k views

LVM snapshots vs. file system snapshots

As far as I know, LVM makes it possible to take snapshots of a volume. There are also a number of file systems (ZFS, Btrfs, reiserfs, ...) which supports snapshots. However, I've never understood the ...
32
votes
8answers
13k views

Delete 10M+ files from ZFS, effectively

I have written a buggy program that has accidentally created about 30M files under /tmp. (The bug was introduced some weeks ago, and it was creating a couple of subdirectories per second.) I could ...
32
votes
9answers
29k views

Is bit rot on hard drives a real problem? What can be done about it?

A friend is talking with me about the problem of bit rot - bits on drives randomly flipping, corrupting data. Incredibly rare, but with enough time it could be a problem, and it's impossible to detect....
31
votes
8answers
41k views

How to delete all but last [n] ZFS snapshots?

I'm currently snapshotting my ZFS-based NAS nightly and weekly, a process that has saved my ass a few times. However, while the creation of the snapshot is automatic (from cron), the deletion of old ...
31
votes
6answers
41k views

ZFS best practices with hardware RAID

If one happens to have some server-grade hardware at ones disposal, is it ever advisable to run ZFS on top of a hardware-based RAID1 or some such? Should one turn off the hardware-based RAID, and run ...
30
votes
5answers
28k views

Ext4 vs. XFS vs. Btrfs vs. ZFS for NAS [closed]

My use case: I have Ubuntu Server 18.04 installed on an M.2 SSD. I have a 4TB HDD I want to add as storage. Since it's mostly for large media files and backups, it won't be written to very often. ...
29
votes
1answer
6k views

ZFS endless resilvering

I have a large (> 100TB) ZFS (FUSE) pool on Debian that lost two drives. As the drives failed, I replaced them with spares until I could schedule an outage and physically replace the bad disks. When ...
29
votes
8answers
8k views

Write speed requirement : 1.1GB/s possibilities?

We will have a machine at work, that on peak performance, should be able to push 50 ("write heads") x 75GB of data per hour. That's peak performance of ~1100MB/s write speed. To get that from the ...
29
votes
2answers
31k views

How to perform incremental / continuous backups of zfs pool?

How can zfs pools be continuously/incrementally backed up offsite? I recognise the send/receive over ssh is one method however that involves having to manage snapshots manually. There are some tools ...
28
votes
2answers
14k views

ZFS RAID and LUKS encryption in Linux

I'm planning to setup a set of 3x 2TB 7200rpm drives as a LUKS-encrypted Z-RAID pool in Linux (for a NAS solution). My understanding of the problem at hand is that the only way to achieve this is to ...
27
votes
2answers
51k views

Transparent compression filesystem in conjunction with ext4

I am trying to test a project that needs compressed storage with use of the ext4 file system since the application I use relies on ext4 features. Are there any production/stable solutions out there ...
27
votes
2answers
7k views

ZFS Data Loss Scenarios

I'm looking toward building a largish ZFS Pool (150TB+), and I'd like to hear people experiences about data loss scenarios due to failed hardware, in particular, distinguishing between instances where ...
24
votes
4answers
3k views

If a RAID5 system experiences a URE during rebuild, is all the data lost?

I understand the argument regarding larger drives' increased likelihood of experiencing a URE during a rebuild, however I'm not sure what the actual implications are for this. This answer says that ...
24
votes
2answers
27k views

For L2ARC and ZIL: is it better to have one large SSD for both, or two smaller SSDs?

Main references ZFS L2ARC (Brendan Gregg) (2008-07-22) and ZFS and the Hybrid Storage Concept (Anatol Studler's Blog) (2008-11-11) include the following diagram: Question Should I interpret the ...
23
votes
1answer
21k views

Hosting a ZFS server as a virtual guest

I'm still new to ZFS. I've been using Nexenta but I'm thinking of switching to OpenIndiana or Solaris 11 Express. Right now, I'm at a point of considering virtualizing the ZFS server as a guest within ...
23
votes
2answers
30k views

Clear a permanent ZFS error in a healthy pool

I scrubbed my pool today, and after the scrub finished, I noticed there was an error that corrupted a file. I didn't care about the file, so I deleted it. Unfortunately, the error remains (now ...
23
votes
2answers
17k views

How large is my ZFS dedupe table at the moment?

I have read a lot of information about planning RAM requirements forZFS deduplication. I've just upgraded my file server's RAM to support some very limited dedupe on ZFS zvols which I cannot use ...
22
votes
2answers
41k views

How can I add one disk to an existing raidz zpool?

I have an OpenSolaris server with a zpool backupz comprised of four SCSI drives: -bash-3.2# zpool status backupz pool: backupz state: ONLINE scrub: none requested config: NAME ...
22
votes
7answers
14k views

How does BTRFS compare to ZFS? [closed]

I am considering which OS and filesystem to use on some new servers I have and am considering either Free BSD with ZFS, or Linux with BTRFS. The programs I have run on both systems, so the only ...
21
votes
4answers
41k views

Moving a ZFS filesystem from one pool to another

I am extending a Solaris 10 U8 server with an extra storage pool in addition to the root rpool. What is the most effective / simple / reliable way of moving particular ZFS filesystem(s) from rpool to ...
21
votes
3answers
16k views

FreeBSD: How to know real file size on zfs with compression on?

I'm using zfs on my FreeBSD 9.0 x64 and pretty happy with it, but I find it hard to count directory real, not compressed, size. Surely I can walk over the directory and count every file size with ls,...
21
votes
2answers
1k views

Sanity check on 40TB server configuration

I've got 40 years in computing, but I've never had to build a server quite like this one, so this might be a n00b question. I have a client that is going to offer ultra-high def music files for ...
19
votes
2answers
20k views

ZFS performance: do I need to keep free space in a pool or a file system?

I know that the performance of ZFS heavily depends on the amount of free space: Keep pool space under 80% utilization to maintain pool performance. Currently, pool performance can degrade when a pool ...
19
votes
4answers
29k views

Are ZFS clustered filesystems possible?

Is it possible to create a ZFS cluster? Or would you need to go the seemingly ugly (to me at least) route of ZFS with UFS formatted pools governed by GlusterFS? The idea is to see if it is possible ...
18
votes
2answers
4k views

What does a permanent ZFS error indicate?

Several permanent errors were reported on my zpool today. pool: seagate3tb state: ONLINE status: One or more devices has experienced an error resulting in data corruption. Applications ...
18
votes
3answers
3k views

150 TB and growing, but how to grow?

My group currently has two largish storage servers, both NAS running debian linux. The first is an all-in-one 24-disk (SATA) server that is several years old. We have two hardware RAIDS set up on it ...
18
votes
1answer
5k views

Is RAID-Z on a single hard disk drive stupid?

Obviously, if the entire drive dies, then RAID-Z on a single disk will not help. But what about other types of errors? From my experience, I sometimes have a file that I can not read. On Mac OS&...
18
votes
3answers
19k views

Should I create ZFS zpools with whole disks or partitions?

I am making zpools on FreeBSD machine. While creating zpools I observe these two cases: If I take raw disks and create zpool then I am able to form zpools and they are working perfectly. If I format ...
17
votes
3answers
10k views

Non-ECC memory with ZFS: a stupid idea?

I have a new server and am planning to upgrade the paltry 2 GB of memory to the maximum of 16 GB. (Theoretically 8 GB is the limit, but empirically 16 GB has been shown to work.) Some guides advise ...
17
votes
3answers
81k views

ZFS - Is RAIDZ-1 really that bad?

I have an NAS server with 4x 2TB WD RE4-GP drives in a RAID10 configuration (4TB usable). I'm running out of space (<1TB usable space left). I have $0 to spend on bigger/more drives/enclosures. I ...
16
votes
14answers
18k views

Best compression for ZFS send/recv

I'm sending incremental ZFS snapshots over a point-to-point T1 line and we're to a point where a day's worth of snapshots can barely make it over the wire before the next backup starts. Our send/recv ...
16
votes
5answers
35k views

Need to identify disk in zpool … how?

I need to replace a bad disk in a zpool on FreeNAS. zpool status shows gptid/5fe33556-3ff2-11e2-9437-f46d049aaeca UNAVAIL 0 0 0 cannot open How do I find the serial # of that disk? ...
16
votes
5answers
9k views

ZFS and SAN — best practices?

Most discussions of ZFS suggest that the hardware RAID be turned off and that ZFS should directly talk to the disks and manage the RAID on the host (instead of the RAID controller). This makes sense ...
15
votes
7answers
61k views

Disabling RAID feature on HP Smart Array P400

I'm planning to use ZFS on my system (HP ML370 G5, Smart Array P400, 8 SAS disk). I want ZFS to manage all disks individually, so it can utilize better scheduling (i.e. I want to use software RAID ...
15
votes
6answers
5k views

Backing up a MySQL database via ZFS snapshots

I've found a number of sites talking about doing exactly this, but I'm missing a few important details. The general steps are Run FLUSH TABLES WITH READ LOCK Take the ZFS snapshot Run UNLOCK TABLES ...
15
votes
1answer
4k views

FREENAS: Why isn't mv command instant within a RAIDZ1 volume?

I'm currently 'reorganizing' file structure within a RAIDZ1 volume. Moving directories from one dataset to another, which are both contained on the same volume. SSH'ed into the machine and did a ...
15
votes
7answers
5k views

recommendations for efficient offsite remote backup solution of vm's

I am looking for recommendations for backing up my current 6 vm's(and soon to grow to up to 20). Currently I am running a two node proxmox cluster(which is a debian base using kvm for virtualization ...
14
votes
2answers
20k views

ZFS: Mirror vs. RAID-Z

I'm planning on building a file server using OpenSolaris and ZFS that will provide two primary services - be an iSCSI target for XenServer virtual machines & be a general home file server. The ...
14
votes
1answer
4k views

ZFS: re-compress existing files after change in compression algorithm

I have a pool that was created in 2011, using lzjb compression, and it wasn't until a couple of years later that an upgrade allowed me to set the compression to lz4. I estimate that at least 20% of ...
14
votes
1answer
8k views

Why does `zfs list` and `zpool list` report very different sizes for my raidz2 pools?

I have a ZFS server with 8 zpools. Each pool is 12 6TB disks in a 10+2 RAIDZ configuration. So, each pool has a raw storage space of 12*6=72 TB and usable space of 10*6=60 TB. However, I see different ...
14
votes
4answers
16k views

Tuning ZFS scrubbing, 141KB/s running for 15 days

A pretty basic system running mirror+stripe on 7.2k rpm sas disks, not particularly loaded. No dedup, compression on all datasets. Scrub has been running for 15 days at the speed of a dead snail. Is ...
13
votes
2answers
3k views

How to big scale backup Gitlab?

When asking Gitlab support on how to do a 3TB backup on ones on-premise Gitlab they reply use our tool that produces a tarball. This just seams wrong to me on all levels. This tarball contains the ...
13
votes
6answers
40k views

ZFS SAS/SATA controller recommendations

I've been working with OpenSolaris and ZFS for 6 months, primarily on a Sun Fire x4540 and standard Dell and HP hardware. One downside to standard Perc and HP Smart Array controllers is that they do ...
13
votes
5answers
9k 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 ...
13
votes
3answers
30k 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 ...

1
2 3 4 5
25