5 ms·

TL;DR: 1. Author dislikes ZFS because you can't grow and shrink a pool however you want. 2. Author likes BTRFS because it implements more flexible grow/shrink

by gnoway 12y ago

TL;DR: 1. Author dislikes ZFS because you can't grow and shrink a pool however you want. 2. Author likes BTRFS because it implements more flexible grow/shrink, but finds that in other ways it's unstable, and is unhappy that BTRFS doesn't let you have arbitrary numbers of parity drives.

louwrentius 12y ago
Correct TLDR. But with BTRFS it's not about 6 parity drives. It's about not support tripple-parity or even RAID60. Features supported by ZFS since eons.
- bsder 12y ago
  As noted above by BrainInAJar, vdev removal just hit the Illumos ZFS tree. So, the ink is barely dry on it as well.
23david 12y ago
The author wants zfs to support growing and shrinking pools in a specific way that it doesn't support. However it's clear from the docs that you can grow zfs pools by adding new vdevs. Shrinking a pool is not possible. In practice I haven't seen the inability to shrink pools as an issue. I simply do not create pools from entire disks and use partitions instead. For example each drive is split into 5 partitions. And if I need to grow a pool I add another partition across all my disks to the pool as a new vdev. This also allows me to have multiple pools on each system that have different Raid-z levels based on different app reqs.
- louwrentius 12y ago
  It is clear from the article that I acknowledge this fact but it is a more convoluted, less flexible solution that wastes space. BTRFS shows how it can and should be done.
- tw04 12y ago
  Actually, you can shrink pools now. http://blog.delphix.com/alex/2015/01/15/openzfs-device-removal/ http://blog.delphix.com/alex/2015/01/15/openzfs-device-remov...
bsder 12y ago
> 1. Author dislikes ZFS because you can't grow and shrink a pool however you want. I believe that this was on the future timeline for ZFS. It required something like the ability to rewrite metadata or something. The problem is that nobody really cares about this outside of a very few individual users. Anybody enterprise just buys more disks or systems. Anybody actually living in the cloud has to deal with entire systems/disks/etc. falling over so ZFS isn't sufficiently distributed/fault tolerant. So, you have to be an individual user, using ZFS, in a multiple drive configuration to care. That's a really narrow subset of people, and the developers probably give that feature the time they think it deserves (ie. none).
- BrainInAJar 12y ago
  vdev removal is in the canonical source of illumos at this point: http://blog.delphix.com/alex/2015/01/15/openzfs-device-removal/ http://blog.delphix.com/alex/2015/01/15/openzfs-device-remov...
  - bsder 12y ago
    Thanks. This has been on the timeline for several years now. Nice to see that it finally hit. IIRC, there were some other nice things that this enabled as well.
  - mahrens 12y ago
    ZFS device removal is on its way but not quite in illumos yet. From Alex's blog post: "We’ll publish the code when we ship our next release, probably in March [2015], [and we will] integrate into Illumos once we address all the future work issues."
- louwrentius 12y ago
  Isn't it funny then that BTRFS supports growing and shrinking? Sounds like it's not such an edge case at all. BTRFS is also focussed on the enterprise, yet it is implemented.
  - bsder 12y ago
RexRollman 12y ago
Shrinking the filesystem is something I have never needed to do since becoming interested in computers in 1992. The only times I have really read about it is when people want to make room for a second OS. To me, this doesn't seem like a big deal.
- vacri 12y ago
  I've seen people shrink filesystems to clone whiteboxes, and I can see some use cases in the embedded world, though these probably aren't the places you want to use zfs or btrfs.

by gnoway 12y ago

louwrentius 12y ago

Correct TLDR. But with BTRFS it's not about 6 parity drives. It's about not support tripple-parity or even RAID60. Features supported by ZFS since eons.

bsder 12y ago
As noted above by BrainInAJar, vdev removal just hit the Illumos ZFS tree. So, the ink is barely dry on it as well.

23david 12y ago

The author wants zfs to support growing and shrinking pools in a specific way that it doesn't support. However it's clear from the docs that you can grow zfs pools by adding new vdevs. Shrinking a pool is not possible. In practice I haven't seen the inability to shrink pools as an issue. I simply do not create pools from entire disks and use partitions instead. For example each drive is split into 5 partitions. And if I need to grow a pool I add another partition across all my disks to the pool as a new vdev. This also allows me to have multiple pools on each system that have different Raid-z levels based on different app reqs.

louwrentius 12y ago
It is clear from the article that I acknowledge this fact but it is a more convoluted, less flexible solution that wastes space. BTRFS shows how it can and should be done.
tw04 12y ago
Actually, you can shrink pools now. http://blog.delphix.com/alex/2015/01/15/openzfs-device-removal/ http://blog.delphix.com/alex/2015/01/15/openzfs-device-remov...

bsder 12y ago

> 1. Author dislikes ZFS because you can't grow and shrink a pool however you want. I believe that this was on the future timeline for ZFS. It required something like the ability to rewrite metadata or something. The problem is that nobody really cares about this outside of a very few individual users. Anybody enterprise just buys more disks or systems. Anybody actually living in the cloud has to deal with entire systems/disks/etc. falling over so ZFS isn't sufficiently distributed/fault tolerant. So, you have to be an individual user, using ZFS, in a multiple drive configuration to care. That's a really narrow subset of people, and the developers probably give that feature the time they think it deserves (ie. none).

BrainInAJar 12y ago
vdev removal is in the canonical source of illumos at this point: http://blog.delphix.com/alex/2015/01/15/openzfs-device-removal/ http://blog.delphix.com/alex/2015/01/15/openzfs-device-remov...
- bsder 12y ago
  Thanks. This has been on the timeline for several years now. Nice to see that it finally hit. IIRC, there were some other nice things that this enabled as well.
- mahrens 12y ago
  ZFS device removal is on its way but not quite in illumos yet. From Alex's blog post: "We’ll publish the code when we ship our next release, probably in March [2015], [and we will] integrate into Illumos once we address all the future work issues."
louwrentius 12y ago
Isn't it funny then that BTRFS supports growing and shrinking? Sounds like it's not such an edge case at all. BTRFS is also focussed on the enterprise, yet it is implemented.
- bsder 12y ago

RexRollman 12y ago

Shrinking the filesystem is something I have never needed to do since becoming interested in computers in 1992. The only times I have really read about it is when people want to make room for a second OS. To me, this doesn't seem like a big deal.

vacri 12y ago
I've seen people shrink filesystems to clone whiteboxes, and I can see some use cases in the embedded world, though these probably aren't the places you want to use zfs or btrfs.