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12

Please don't do this. If you're going to run ZFS on Linux, do it bare metal without a virtualization layer. All-on-one virtualization and ZFS solutions are cute, but it's not worth the effort in production. As far as drives are concerned, you can use SATA disks on an HP Smart Array controller as well as the LSI 9211-8i controller. In a ZFS configuration, ...


12

FreeNAS is a NAS solution, as such, some technical choices are hidden behind whatever firmware, system or GUI such appliance can use. If you get the partition schema used on a given disk inside a ZFS pool made with FreeNAS (small VM example): $ glabel status Name Status Components ...


12

I think you should reconsider your use of FreeNAS. You've had an uncharacteristically. large. number. of issues. with. your. FreeNAS. installation(s). over. the years. Many of these issues were planning and ZFS design problems. It may be time to refactor or rebuild your environment now that you have some knowledge of best or better-practices.


11

Don't go down the road of breaking the ZFS array to "rotate" disks offsite. As you've seen, the rebuild time is high and the resilvering process will read/verify the used size of the dataset. If you have the ability, snapshots and sending data to a remote system is a clean, non-intrusive approach. I suppose you could go through the process of having a ...


9

You really can't monitor the array status that well on your platform. One tacky option is cciss_vol_status, but it's far from the mainstream approach. This is kind of a bad combination of hardware and software. FreeBSD ProLiant support is a bit Meh... Okay, it's actually worse than that... So a few things to consider: ZFS is a software RAID and volume ...


9

I use both, but prefer ZFS. ZFS on Linux has been very good to me, but isn't the "fix all" for every situation. A typical server will look like this: (Remember, I usually use hardware RAID and mostly use ZFS as a flexible volume manager) Hardware RAID with a logical volume comprised of underlying disks. That array will be carved into a small OS volume ...


9

This is a udev issue that seems to be specific to Debian and Ubuntu variants. Most of my ZFS on Linux work is with CentOS/RHEL. Similar threads on the ZFS discussion list have mentioned this. See: scsi and ata entries for same hard drive under /dev/disk/by-id and ZFS on Linux/Ubuntu: Help importing a zpool after Ubuntu upgrade from 13.04 to 13.10, device ...


9

Yes, it all works... Dedupe, compression, checksumming, caching are all present when using zvols in ZFS. But I really prefer NFS for virtualization purposes because of the transparency. But either will do the job. Can you elaborate a bit more on your intended use for ZFS? I ask because there are a lot of potential design/planning issues. Take a good read ...


8

There is no need to create a loop device, you can simply use the file itself as a vdev: zpool create test /tank/test/zpool


7

One of the servers that I administrate runs the type of configuration that you describe. It has six 1TB hard drives with a LUKS-encrypted RAIDZ pool on it. I also have two 3TB hard drives in a LUKS-encrypted ZFS mirror that are swapped out every week to be taken off-site. The server has been using this configuration for about three years, and I've never had ...


6

zfs receive is atomic indeed. The incoming snapshot is not available until the receive completes successfully. The receiving file system is unavailable (unmounted) during the reception of an incremental snapshot. In the case of a full file system snapshot, there is no receiving file system in the first place. Note that atomic doesn't means instantaneous, ...


6

You are thinking about things from the wrong level, is all. If you move a file within the confines of a single ZFS dataset, it will react similarly to what you're expecting. If you move a file within the confines of a pool, but between datasets, it is a real move. Yes, technically the data just went from point A to point B and both points are on the same ...


6

ZFS pool information is not stored in a plain text file. Information about a pool is stored on the disks themselves. ZFS pool information can also be written to a ZFS cache file, but it does not contain mount point information. If you want to get mount point values for your ZFS pools you can use the following: zfs get mountpoint <pool name> zfs get ...


6

RAIDZ2 isn't going to be especially fast with 4 SATA disks... on a server with 4GB of RAM... with a weak processor... and without any level of ZFS tuning. ZFS mirrors would have been a better choice for a few reasons as well. However, have you measured actually filesystem performance? What are you expecting to see? That's about right, based on the gear ...


5

Using Consumer grade disks in server grade HW is possible though not recomended if you are going to use the support from the vendor. They will bitch like hell why you replaced the perfectly supported drives with unsuported such. Aside from that there is no problem to do it and backblaze proved it ...


5

Good news is you can change the vdev configuration scheme by exporting and re-importing your pool. (from ZFS on Linux docs) admin@Test-ZFS:~$ sudo zpool status tankz pool: tankz state: ONLINE scan: resilvered 15K in 0h0m with 0 errors on Tue Feb 25 16:36:18 2014 config: NAME STATE READ WRITE CKSUM tankz ONLINE 0 ...


5

No, this is not possible in your situation. For other ZFS best practices and limitations, take a look at this blog post.


5

First off, it's worth stating that ZFS is not a supported filesystem for MongoDB on Linux - the recommended filesystems are ext4 or XFS. Because ZFS is not even checked for on Linux (see SERVER-13223 for example) it will not use sparse files, instead attempting to pre-allocate (fill with zeroes), and that will mean horrendous performance on a COW ...


5

The first thing to keep in mind is that ZFS should never be used this way. ZFS isn't a common filesystem, it consists of a RAID-layer, filesystem and even fileserver, as ZFS natively supports NFS for example. Think ZFS as an hardware controller, when the ZFS is the software running in the controller, your system RAM is the controller cache (ARC) and your ...


5

I hate to say this, but do you know that you were basically adding unraided disks to your pool? The command you provided basically says, "Add another disk to pool nas and stripe it with the existing disks." Is that what you meant to do? The pool is done at this point, especially if anything was written to the bad disk. If this were a pair of mirrors, the ...


5

This came up in discussion on the ZFS mailing list. The kernel ABI changed between 0.6.2 and 0.6.3 in such a way that 0.6.3 user-land tools can't interact with 0.6.2 kernel modules, which is the configuration after upgrading to 0.6.3. According to numerous messages on this list, the right approach is simply to reboot. This is covered in the ZFS ...


5

That looks like...a bug. In fact, it is a bug. The ZFS userland is updated, but the kernel modules aren't being updated by DKMS. This assertion is caused by the version mismatch. You can work around it by a process given in a comment to the bug, by removing the old kernel modules and then reinstalling everything. $ find /lib/modules/$(uname -r)/extra -name ...


5

$ sudo find /lib/modules/$(uname -r)/updates -name "splat.ko" -or -name "zcommon.ko" -or -name "zpios.ko" -or -name "spl.ko" -or -name "zavl.ko" -or -name "zfs.ko" -or -name "znvpair.ko" -or -name "zunicode.ko" | xargs rm -f $ sudo apt-get install --reinstall ubuntu-zfs $ sudo apt-get install --reinstall $(dpkg-query --show --showformat='${binary:Package}\n' ...


5

The explanation for the JBOD resiliency you read about on the mailing list is probably something like a set of RAIDZ3 vdevs and enclosures... Say 8 disks per RAIDZ3 (5+3), and 5 (or 8?) enclosures, such that the vdevs were comprised of a single disk from each enclosure. But for realz, I would not do 1PB of storage without some degree of ...


5

Yes, it's still the convention, and yes, it holds true even as you scale. With ZFS, in fact, you really don't want to get to the 75% mark in your zpool too often. Fragmentation, snapshots and general performance tend to be impacted. If building anew, don't start with anything more than 40% utilization and be sure to plan for growth.


5

I use ZFS on Linux as a volume manager and a means to provide additional protections and functionality to traditional filesystems. This includes bringing block-level snapshots, replication, deduplication, compression and advanced caching to the XFS or ext4 filesystems. See: https://pthree.org/2012/12/21/zfs-administration-part-xiv-zvols/ for another ...


4

While as already answered it is technically doable, beware that what you want to do is not a best practice as you end up with an unbalanced pool with sub optimal performance. All disks in a pool should be of the same size (outside log and cache devices) and all striped vdevs should have the same organization. You break both of these rules with mixing 2 TB ...


4

Set autoreplace=on for your pool and use like or similar disks. Resilvering occurs automatically when that flag is set on the pool. If a hot-spare is defined in the pool, it will also rebuild automatically if autoreplace is on. There's nothing more to really consider.


4

Scrub your pool again (if you haven't already): zpool scrub zstorage That error is telling you that inode <0x9f115> is corrupt (deleting the file broke the filename->inode mapping, so it's just reporting the inode now). Either something still has the file open or the metadata just needs to be cleaned up (which a scrub should do). To clear the error if ...


4

I'd suggest dedicated drives for OS and dedicated disks for data. NexentaStor is software RAID and the loss of an OS disk can be painful. You can combine L2ARC and ZIL, but the class of SSDs you're probably using won't be helpful as ZIL devices. I understand the desire to try to use all of these ZFS features, but you really have to do it the right way. I ...



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