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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144
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2answers
28k 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?
13
votes
6answers
29k 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 ...
20
votes
1answer
15k 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 ...
16
votes
5answers
12k 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 ...
1
vote
1answer
2k views

My OpenSolaris Server hangs when writing large files after upgrading zpool

yesterday I added new harddrives(four as a raidz1 and one as hot-spare) to a opensolaris server, after extending the zpool the server hangs when writing large files but not when reading large files(...
8
votes
5answers
31k 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 ...
8
votes
2answers
2k views

ZFS - destroying deduplicated zvol or data set stalls the server. How to recover?

I'm using Nexentastor on a secondary storage server running on an HP ProLiant DL180 G6 with 12 Midline (7200 RPM) SAS drives. The system has an E5620 CPU and 8GB RAM. There is no ZIL or L2ARC device. ...
21
votes
2answers
5k 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 ...
10
votes
5answers
7k views

Best filesystem choices for NFS storing VMware disk images

Currently we use an iSCSI SAN as storage for several VMware ESXi servers. I am investigating the use of an NFS target on a Linux server for additional virtual machines. I am also open to the idea of ...
11
votes
3answers
2k views

ZFS: How do you restore the correct number of copies after losing a drive?

With zfs, if you have copies=2 and then you lose a drive containing some of those copies, how do you tell the system that it should make a new copy of the data blocks for the affected files? Or does ...
14
votes
2answers
17k 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 ...
11
votes
2answers
16k 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 ...
10
votes
3answers
5k views

ZFS - Impact of L2ARC cache device failure (Nexenta)

I have an HP ProLiant DL380 G7 server running as a NexentaStor storage unit. The server has 36GB RAM, 2 LSI 9211-8i SAS controllers (no SAS expanders), 2 SAS system drives, 12 SAS data drives, a hot-...
9
votes
2answers
14k views

Need to replace disk in zpool … confused

I need to replace a bad disk in a zpool on FreeNAS. zpool status shows pool: raid-5x3 state: ONLINE scrub: scrub completed after 15h52m with 0 errors on Sun Mar 30 13:52:46 2014 config: ...
11
votes
1answer
8k views

Is calculating IOPS for ZFS RAIDZ different then calculating IOPS for RAID5 & RAID6?

When calculating IOPS for traditional RAID arrays, one could use the following formula (Borrowed from Getting The Hang Of IOPS v1.3 on Symantec Connect): Ieffective = (n * Isingle) / (READ% + (F * ...
15
votes
2answers
27k 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 ...
13
votes
1answer
2k views

Why did rebooting cause one side of my ZFS mirror to become UNAVAIL?

I just recently migrated a bulk data storage pool (ZFS On Linux 0.6.2, Debian Wheezy) from a single-device vdev configuration to a two-way mirror vdev configuration. The previous pool configuration ...
5
votes
6answers
10k views

MegaRAID JBOD substitute

It seems that certain MegaRAID chips don't support JBOD (unfortunately). I've read online that to make these controllers act as a pass-through, I should configure the disks in RAID0. What RAID0 ...
1
vote
3answers
3k views

Solaris: detect hotswap SATA disk insert

What's the method used on Solaris to get the system to rescan for new disks that have been hot-plugged on a SATA controller? I've got an HP X1600 NAS which had 9 drives configred in a ZFS pool. I've ...
26
votes
1answer
3k 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 ...
12
votes
3answers
7k 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 ...
7
votes
2answers
5k views

What's in my ZFS ARC and L2ARC caches?

I have a simple ZFS setup at home, four disks mirrored, 8GB ram and 120GB Intel X25-M SSD for L2ARC. I ran zpool add poolname cache cXtXdX then generated load and eagerly tracked the warming process ...
4
votes
1answer
3k views

ZFS (NexentaStor) and 4k Advanced Format Partition Alignment

I have a storage system that contains 8 x 1TB drives that use the 4k sector size "Advanced Format". I'm planning to run NexentaStor on this hardware and want to ensure that I'm taking the 4k sector ...
3
votes
4answers
9k views

ZFS - how to partition SSD for ZIL or L2ARC use?

I'm working with a Sun x4540 unit with two pools and newly-installed ZIL (OCZ Vertex 2 Pro) and L2ARC (Intel X25-M) devices. Since I need to keep these two pools in the near-term, I'd like to know how ...
10
votes
4answers
6k views

Can I trust that ZFS is consistent between Linux and FreeBSD?

I'm planning to build a FreeNAS box sometime soon, but if ZFS on Linux eventually proves to be reliable, I might want to switch, just to have a more familiar OS. So I'm wondering if I can trust that ...
5
votes
1answer
4k views

ZFS on Linux/Ubuntu: Help importing a zpool after Ubuntu upgrade from 13.04 to 13.10, device IDs have changed

I have updated Ubuntu from version 13.04 to version 13.10, only to discover that the SATA disks IDs have changed, and my ZFS pool now fails. On new Ubuntu 13.10 the disk IDs are now ata-* instead of ...
3
votes
2answers
6k views

FreeNAS confusion: not sure what happened. raidz1 “DEGRADED”, disk “FAULTED”

Sorry for the long narrative, but I'm thoroughly confused. I'm using FreeNAS-8.0.4-RELEASE-p2-x64 (11367) on a box with 5x3TB SATA disks configured as a raidz volume. A few days ago, the console ...
6
votes
1answer
2k views

Does ZFS replace the need for hardware/software RAID?

I want to provide protection against data loss on my servers. Typically, I'd use hardware RAID 1 or 5, but I've been reading up on ZFS. Is it correct that ZFS itself provides RAID 1 or 5 like data ...
5
votes
3answers
4k views

PAM: Execute a command before pam_mkhomedir?

When a user logs into a system and there is no home directory, we would like to to create the user's home directory using pam_mkhomedir. This is a common practice. Here's a quick description of ...
4
votes
3answers
4k views

zpool status reports error … what next?

On our FreeNAS server, zpool status gives me: pool: raid2 state: ONLINE status: One or more devices has experienced an unrecoverable error. An attempt was made to correct the error. ...
4
votes
3answers
4k views

ZFS: Removing files from snapshots?

Say I have a dataset with 100 snapshots and want to rm -rf all folders named "cache" in all snapshots. I want to actually free up the space, not just hide it away in layers of snapshots, so making a ...
3
votes
2answers
1k views

Increase space of ZFS pool over iSCSI SAN, online

I have an iSCSI volume of 96GB on SAN, which has ZFS pool implemented on it. i have resized the size of SAN volume from 96 to 120GB, but the zpool list only shows the old space (96GB). how to achieve ...
0
votes
2answers
1k views

Debug Nexenta/OpenSolaris core files?

I have a Sun x4540 that was recently converted to NexentaStor Enterprise Edition from an earlier OpenSolaris. The system disks were wiped and the zpools were exported and reimported. I'm hosting ...
43
votes
12answers
35k 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 ...
9
votes
6answers
10k views

Recommendations on ZFS on FreeBSD as a NAS box?

Please note that the answers on this page are from 2009, and should not be relied on as gospel. If you have a specific question about zfs then please click the Ask a Question button and ask a specific ...
24
votes
4answers
7k 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 ...
10
votes
2answers
8k views

How to upgrade a ZFS RAID-Z array to larger disks on OpenSolaris?

I'm planning on installing OpenSolaris on my home server (right now it has Linux) and I would like to know how to prepare for upgrading the server to have larger hard drives in the future. Now the ...
7
votes
6answers
3k views

hardware recommendations for a DIY storage system based on ZFS [closed]

Looking to make use of old server lying idle as a proof-of-concept ...here are specs Dell PE 2900: Xeon 5110 - 2P, 12 GB RAM, 8x 300 GB 15K drives, Perc 5i+256 MB cache what additional h/w would be ...
14
votes
5answers
15k 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 ...
9
votes
2answers
6k views

KVM on Illumos (OpenIndiana vs. SmartOS)

I'm considering virtualizing a number of guests onto a single server running a recent port of KVM to Illumos. It sounds like my two primary options will be OpenIndiana and SmartOS. The distribution ...
6
votes
3answers
4k views

Where can I find introductory documentation for ZFS?

I recently installed OpenIndiana because of an interest in ZFS. I like the feature-list of ZFS, but I'm having a hard time wrapping my head around how to configure it. All of the documentation I ...
9
votes
4answers
17k 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 ...
26
votes
7answers
16k 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....
8
votes
5answers
13k views

ZFS Sync over unreliable, slow WAN. ZFS replication, or rsync?

I've been tasked with making an off-site backup work over the WAN. Both storage boxes are FreeBSD based NAS boxes running ZFS. Once or twice a week, 15-60 gigs of photography data gets dumped to the ...
16
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 ...
6
votes
2answers
3k views

Is there a tool for managing FreeBSD jails that knows about ZFS?

ZFS under FreeBSD lets one assign filesystems to a jail, such that an account in the jail with the appropriate privileges can access the filesystem, create new subordinate filesystems, and so forth. ...
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 ...
12
votes
2answers
7k 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 ...
10
votes
1answer
6k 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 ...
5
votes
4answers
14k views

How to determine which disk failed in a FreeNAS / ZFS setup

I'm building out a FreeNAS based server in a Supermicro X6DHE-XB 3U enclosure with 4G of RAM, 16 SATA hot-swap bays. It comes with 2x8 port 3Ware RAID cards, but I'm planning on just using the ZFS ...