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ZFS 2.3 released with ZFS raidz expansion

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Re: ZFS 2.3 released with ZFS raidz expansion

#21

Post by Mashimo »

zelcon wrote: post #18
jfreax wrote: post #14

Earlier quoted context omitted.

I'm not yet familiar with zfs and couldn't find it in the release note: Does expansion only works with disk of the same size? Or is adding are bigger/smaller disks possible or do all disk need to have the same size?

You need to buy the same exact drive with the same capacity and speed. Your raidz vdev be as small and as slow as your smallest and slowest drive. btrfs and the new bcachefs can do RAID with mixed drives, but I can’t trust either of them with my data yet.

> You need to buy the same exact drive

AFAIK you can add larger and faster drives, you will just not get any benefits from it.

Re: ZFS 2.3 released with ZFS raidz expansion

#22

Post by TiredOfLife »

mustache_kimono wrote: post #9
cm2187 wrote: post #8

Earlier quoted context omitted.

It is possible with windows storage space (remove drive from a pool) and mdadm/lvm (remove disk from a RAID array, remove volume from lvm), which to me are the two major alternatives. Don't know about unraid.

> It is possible with windows storage space (remove drive from a pool) and mdadm/lvm (remove disk from a RAID array, remove volume from lvm), which to me are the two major alternatives. Don't know about unraid. Perhaps I am misunderstanding you, but you can offline and remove drives from a ZFS pool. Do you mean WSS and mdadm/lvm will allow an automatic live rebalance and then reconfigure the drive topology?

Storage Spaces doesn't dedicate drive to single purpose. It operates in chunks (256MB i think). So one drive can, at the same time, be part of a mirror and raid-5 and raid-0. This allows fully using drives with various sizes. And choosing to remove drive will cause it to redistribute the chunks to other available drives, without going offline.

Re: ZFS 2.3 released with ZFS raidz expansion

#23

Post by bpye »

Mashimo wrote: post #21
zelcon wrote: post #18

Earlier quoted context omitted.

You need to buy the same exact drive with the same capacity and speed. Your raidz vdev be as small and as slow as your smallest and slowest drive. btrfs and the new bcachefs can do RAID with mixed drives, but I can’t trust either of them with my data yet.

> You need to buy the same exact drive AFAIK you can add larger and faster drives, you will just not get any benefits from it.

You can get read speed benefits with faster drives, but your writes will be limited by your slowest.

Re: ZFS 2.3 released with ZFS raidz expansion

#26

Post by ryao »

cm2187 wrote: post #3
scrp wrote: post #2

After years in the making ZFS raidz expansaion is finally here. Major features added in release: - RAIDZ Expansion: Add new devices to an existing RAIDZ pool, increasing storage capacity without downtime. - Fast Dedup: A major performance upgrade to the original OpenZFS deduplication functionality. - Direct IO: Allows bypassing the ARC for reads/writes, improving performance in scenarios like NVMe devices where cachi…

But I presume it is still not possible to remove a vdev.

That was added a while ago:

https://openzfs.github.io/openzfs-docs/man/master/8/zpool-re...

It works by making a readonly copy of the vdev being removed inside the remaining space. The existing vdev is then removed. Data can still be accessed from the copy, but new writes will go to an actual vdev while data no longer needed on the copy is gradually reclaimed as free space as the old data is no longer needed.

Re: ZFS 2.3 released with ZFS raidz expansion

#27

Post by lutorm »

endorphine wrote: post #25

Can someone describe why they would use ZFS (or similar) for home usage?

Apart from just peace of mind from bitrot, I use it for the snapshotting capability which makes it super easy to do backups. You can snapshot and send the snapshots to other storage with e.g zfs-autobackup and it's trivial and you can't screw it up. If the snapshots exist on the other drive, you know you have a backup.

Re: ZFS 2.3 released with ZFS raidz expansion

#28

Post by mustache_kimono »

shiroiushi wrote: post #15
jfreax wrote: post #14

Earlier quoted context omitted.

I'm not yet familiar with zfs and couldn't find it in the release note: Does expansion only works with disk of the same size? Or is adding are bigger/smaller disks possible or do all disk need to have the same size?

As far as I understand, ZFS doesn't work at all with disks of differing sizes (in the same array). So if you try it, it just finds the size of the smallest disk, and uses that for all disks. So if you put an 8TB drive in an array with a bunch of 10TB drives, they'll all be treated as 8TB drives, and the extra 2TB will be ignored on those disks. However, if you replace the smallest disk with a new, larger drive, and r…

> As far as I understand, ZFS doesn't work at all with disks of differing sizes (in the same array).

This might be misleading, however, it may only be my understanding of word "array".

You can use 2x10TB mirrors as vdev0, and 6x12TB in RAIDZ2 as vdev1 in the same pool/array. You can also stack as many unevenly sized disks as you want in a pool. The actual problem is when you want a different drive topology within a pool or vdev, or you want to mismatch, say, 3 oddly sized drives to create some synthetic redundancy level (2x4TB and 1x8TB to achieve two copies on two disks) like btrfs does/tries to do.

Re: ZFS 2.3 released with ZFS raidz expansion

#29

Post by lutorm »

ryao wrote: post #26
cm2187 wrote: post #3

Earlier quoted context omitted.

But I presume it is still not possible to remove a vdev.

That was added a while ago: https://openzfs.github.io/openzfs-docs/man/master/8/zpool-re... It works by making a readonly copy of the vdev being removed inside the remaining space. The existing vdev is then removed. Data can still be accessed from the copy, but new writes will go to an actual vdev while data no longer needed on the copy is gradually reclaimed as free space as the old data is no longer needed.

Although "Top-level vdevs can only be removed if the primary pool storage does not contain a top-level raidz vdev, all top-level vdevs have the same sector size, and the keys for all encrypted datasets are loaded."

Re: ZFS 2.3 released with ZFS raidz expansion

#30

Post by FrostKiwi »

FINALLY!

You can do borderline insane single-vdev setups like RAID-Z3 with 4 disks (3 Disks worth of redundancy) of the most expensive and highest density hard drives money can buy right now, for an initial effective space usage of 25% and then keep buying and expanding Disk by Disk, with the space demand growing, up to something like 12ish disks. Disk prices dropping as time goes on and a spread out failure chance with disks being added at different times.

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