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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2k views

Gluster + ZFS, deadlock during benchmarking: zfs_iput_taskq 100% cpu

First some background: I work at a company that runs a PHP-webapplication. We have a storage backend mounted over NFS on several webservers. Today we have the issue if one webserver writes a file over ...
0
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1answer
5k views

freenas zfs read performance sucks .. why?

I just set up a freenas zfs raid-z2 with 4 drives sata enterprise drives and doing some performance tests. Right now I'm pushing and pulling linux images into the storage. My notebook has a samsung ...
1
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1answer
3k views

Is it possible to remove a drive from zfs?

I have a zfs raid-z1 with too much storage volume. I thought of taking out one volume. Is it possible to remove a drive from a zfs raid storage? thx for your help
4
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1answer
4k views

Is it possible to change zfs raid-z1 to raid-z2 or raid-z3 on freenas?

I have a running freenas zfs on raid-z1. For safety i though of increasing parity. Enough spare space is available. Is it possible to upgrade a zfs raid-z1 to raid-z2 or raid-z3? thx for your help
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1answer
2k views

ZFS checksum errors: what files are affected?

Here is a zfs pool with checksum errors: NAME STATE READ WRITE CKSUM pool0 ONLINE 0 0 42 c1t1d0 ONLINE 0 0 30 c1t2d0 ONLINE ...
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1answer
177 views

Samba intermittently timing out on writes to a ZFS share

I'm experiencing an odd problem on a file server intermittently failing when writing files. The problem occurs when I try to write a number of files from a (Windows 7) client at once. Intermittently,...
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2answers
563 views

Why does zfs fail to cache this workload when “normal” filesystems cache it completely?

Update: because recordsize defaults to 128k, the amount of data read by the test program is much larger than the ARC on an 8GB system and still slightly larger than the ARC on a 16GB system. Reducing ...
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1answer
2k views

zpool import with missing device

I had two geli-encrypted partitions on separate disk in a zpool as simple disks (no raid*). I didn't want redundancy for all files, only for some selected datasets (for which I set copies=2). Now one ...
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2answers
592 views

Scale-out distributed storage with snapshots

I'm aware there are many similar questions around, several with great answers. I still haven't quite found what I'm looking for though: a distributed, scale-out FS that supports snapshots. Gluster ...
3
votes
1answer
971 views

NexentaStor: how to partition SSD disk?

I'm trying to set up some homegrown storage using a desktop motherboard, 4 x SATA drives and 2 x SSD drives. I'd really like to use NexentaStor for its nice web interface and for it is some ...
7
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1answer
10k 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 ...
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0answers
258 views

zfs recovery after hardware failure

My ZFS storage hardware failed including the rpool disks. I installed a new server and tried to import use zfs import -f poolname. I am able to see the pool and the disk utilized. But I am not able to ...
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1answer
5k views

Using SATA III SSDs for ZFS pools

I'm thinking of building a ZFS server optimized for random access (PostgreSQL database). I figured that I have 2 options: Use pools consisting of the Crucial M500 960 GB SATA III SSDs. Enterprise ...
1
vote
1answer
261 views

ZFS booting troubles

I have FreeBSD 8.0, and rebooting arise while zfs scrub was runing. Now when system booting it frezee at moment with ZFS version and ZFS pool version. I can't even login. The question : Is the scrub ...
20
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2answers
789 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 ...
4
votes
2answers
752 views

Is it Possible to Automatically Resilver a ZFS Array On Hotswap

I'm trying to learn about ZFS for a NAS I'm planning on building. I'm trying to understand if the following scenario would be possible to set up. Disclaimer: I know very little about ZFS, so forgive ...
2
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0answers
358 views

ZFS on RedHat configuration

I have to set up a ZFS storage appliance (Oracle ZFS Storage ZS3-2) with NFSv4. The NFS is mounted on a Redhat 6.5 cluster, where the linux users are created (they don`t exist on the appliance). ...
3
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1answer
1k views

ZFS, NFS and Nexenta

Is this message familiar to someone ? zfs-clu-01a rpcmod: [ID 851375 kern.warning] WARNING: svc_cots_kdup no slots free zfs-clu-01a last message repeated 75220 times We have a lot of trouble ...
3
votes
1answer
633 views

“zpool create” hangs indefinitely

I have a Solaris 11.1 machine which has some disks attached to it via an expander (LSISAS2X36) through an LSI 1068 controller. The setup used to work quite decently, but as I have added another batch ...
5
votes
1answer
120 views

Is “zfs receive” an atomic operation?

Is zfs receive an atomic operation? Can a process read from or write to the receiving file system during the zfs receive operation? Can a process read any of the files in the incoming snapshot ...
3
votes
1answer
127 views

Expanding ZFS on MDRaid?

I had a 4-disk mdraid of 8.12TB with zfsonlinux's ZFS: # zpool status pool: tank state: ONLINE scan: none requested config: NAME STATE READ WRITE CKSUM tank ...
2
votes
1answer
8k views

FreeNAS, Do I need 1GB per TB of usable storage, or 1GB of memory per TB of physical disc?

The title says it all. When setting up free NAS, do I need 1GB per TB of usable storage, or 1GB of memory per TB of physical disc?
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4answers
4k views

ZFS: Memory issues with dedup even though zdb -DD looks fine

I've been experimenting with ZFS on a machine with Ubuntu 12.10, 32GB RAM (non-ECC, production system will have ECC) and a 2x2TB Linux-managed RAID1 (will be moved to RAIDZ1 for production). I just ...
3
votes
1answer
492 views

XenServer Linux guest booting off iSCSI SAN (ZFS storage): Will a non-checksumming guest file system still be at risk?

We are storing files on FreeNAS 9.2 using ZFS. I love the data integrity claims made by ZFS, having randomly lost data in the past on servers using ext3, XFS, and ReiserFS that were not mistreated (...
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2answers
696 views

Why does a failed ZFS disk still seem to work fine?

Two disks just failed in my zpool with read/write errors, so I took them out and inserted them in another host, created a zpool just with them, and filled the file system with dd if=/dev/zero of=/...
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1answer
59 views

Choosing a zpool size?

Is there a rule of thumb when to create a new zpool instead of expanding the current? Right now I have 100TB and can either expand with another 100TB or create an extra.
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2answers
2k views

Are consumer class hard disks okay for zfs?

I just recently bought a new server an HP DL380 G6. I replaced the stock smart array p410 controller with an LSI 9211-8i. My plan is use ZFS as the underlying storage for XEN which will run on the ...
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 ...
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1answer
945 views

Debian KVM and location for vm images different than /var/lib/libvirt/images

I have defined storage pool for VMs on ZFS: virsh # pool-dumpxml zfs <pool type='dir'> <name>zfs</name> <uuid>b2fba550-467f-8133-dee8-44ada7d0a807</uuid> <...
2
votes
1answer
224 views

Is in-memory write-cache and ZIL data both written through TXG commits?

ZFS nowadays has an interval of 5 seconds for doing TXG (Transaction Group Commits) of the in-memory write-cache.. How and after how long is ZIL data committed to the rotational media from say, an SSD ...
2
votes
2answers
224 views

zfs regular read pauses

We have a zfs file system running on openindiana with an almost purely read-only workload. Recently we have found that the io is blocked or pauses every 1 minute for around 2-3 seconds. Does anyone ...
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2answers
484 views

Can you add a different size RAIDZ1 to an exists zpool?

For example, I have a 4x2TB RaidZ1 set up right now, but I would like to add only a 3X4TB RaidZ1 in addition to it. Is there a way to do this with zdevs/another Zpool? Thanks
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1answer
1k views

Why is my RAIDZ2 pool larger than the expected size calculation?

I'm building a RAIDZ2 ZFS system, using Ubuntu 13.10 as a base system, and zfsonlinux's packages, having 6 disks dedicated to the pool data and a couple of SSD partitions to do ZIL log and L2ARC cache....
1
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1answer
532 views

SAS IT Mode controllers and SAS Expanders

Lots of semi-related posts, but none that address this scenario. I picked up an LSI SAS1064E-IR based HP Controller. I flashed it with an -IT firmware, and things look somewhat ok. Except that I ...
5
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1answer
3k views

ZFS: bringing a disk online in an unavailable pool

I have a home server using FreeBSD and ZFS that has worked well for the last 5 years, and on several occasions I have successfully replace faulty disks. However, today a minor disaster has happened, ...
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1answer
77 views

Prevent NexentaStor analytics page from timing out

NexentaStor has a handy profiling interface that serves as a front to certain dtrace scripts. It's handy for monitoring realtime IOPS or I/O throughput of the appliance. Unfortunately, this interface ...
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votes
2answers
2k 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 ...
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0answers
262 views

NexentaStor 3.1.5-GA (community ed) won't boot from a CD

I can boot from 3.1.5-GA ISO into a VirtualBox VM. But when I boot from a bootable CD, it stops at "Grub Stage2", and then drops me into a grub rescue shell after a few seconds.. I know very well how ...
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vote
2answers
479 views

SmartOS using ZFS and guest filesystems [closed]

If I do something like RAIDZ2 with 10 or so disks, then on guest operating systems, if I use a filesystem like ext3/4, will the guest filesystem be as safe as if it were also using ZFS? The reason I ...
4
votes
1answer
7k views

How often should I defrag ZFS pools?

I ZFS scrub once a month which takes ~24 hours for the 72TB. For what I can find about how often I should scrub is: very busy pools, once per week not so busy pools, once per month or run a scrub, ...
2
votes
1answer
826 views

ZFS: SAS v SATA - does it matter?

I understand from NEC's white paper, Silent data corruption in disk arrays, that: some SAS drives should have a "T10-DIF" feature to detect silent data corruption; whereas "There is no standard for ...
3
votes
1answer
343 views

FreeBSD 9.2 shows SATA3 drives as SATA2

I'm running FreeBSD 9.2 on an Intel S2600GZ server board with 4 Intel SSDs. Both the server board as well as the disks are SATA3 capable. However, FreeBSD seems to think they are SATA2. Nowhere in ...
3
votes
2answers
2k views

size the write cache ZFS

I would like to add a write cache to my Nexenta. I thought about using 2 SSDs in mirror with a third disc in spare. The problem is: How do I calculate the size of my array to maximize the investment (...
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votes
1answer
1k views

zfs: zpool space map thrashing - ever fixed?

For zpools which are rather full and/or very fragmented I use to enable metaslab debugging (echo metaslab_debug/W1 | mdb -kw) to avoid space map thrashing and the resulting severe write performance ...
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2answers
821 views

Can I remove a vdev from a ZFS pool by rolling back? [closed]

A curiosity related question: Can a VDEV be removed from a ZFS pool by undoing the last pool transactions (zpool import -F) or rolling back to an earlier snapshot?
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votes
2answers
3k views

iSCSI: LUNs per target?

My question relates specifically to ZFS/COMSTAR but I assume is generally applicable to any iSCSI system. Should one prefer to create a target for every LUN that you want to expose? Or is it good ...
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2answers
3k views

ZFS Recover from Faulted Pool State

I have a six disk ZFS raidz1 pool and had a recent failure requiring a disk replacement. No problem normally, but this time my server hardware died before I could do the replacement (but after and ...
3
votes
1answer
860 views

Using ZFS or XFS on a Xen guest running Linux

Background: I'm investigating the viability of using a filesystem other than ext3/4, with the ability to run snapshots for backup and rollback purposes. The servers under consideration are mailbox ...
3
votes
1answer
266 views

ZRAID1 pool size bigger than expected

I have 3x 4TB drives for a ZRAID1 config (single parity drive) After running zpool create data zraid1 sdb sdc sdd I have a volume that's 10.9T in size, which is what I would expect from a stripe ...
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votes
2answers
1k views

Hardware RAID0: what happens when a drive fails?

With a hardware-based RAID0, what happens when a drive fails? For example, on brand name servers like HP DL120G7 with HP P410, when running FreeBSD on a zfs with a zpool mirror, or DragonFly BSD with ...