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ZFS on Linux: Unlistable and disappearing files

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Re: ZFS on Linux: Unlistable and disappearing files

#81
post #77
post #21

At least it's no btrfs. What a disaster that filesystem's been.

i have been using btrfs in production for years now and it has never failed me, and i am doing hundreds of snapshots and send/receiving, i've reconfigured raids on the fly and went from 6 disk raid 10 of mixed size to raid 10 of same size. we have in some cases had many power failures with no data loss. We also have some set up using md raid and some using hardware raid... when i hear people dogging btrfs it just spe…

Are you using btrfs native RAID support? The docs say it's really unstable so I was scared to use it

Re: ZFS on Linux: Unlistable and disappearing files

#82

Wow that's an old Kernel! https://linux.slashdot.org/story/16/01/31/0424221/linux-kern...

While the 2.6.32-696.23.1.el6.x86_64 is an old kernel, it is actually the current kernel for CentOS/RHEL 6. Red Hat has backported a lot of fixes to it and CentOS/RHEL 6 is a distribution that is still under maintenance.

It is still out there in a lot of places and has been in production for a while. That it is old, is a feature, it also means that it is incredibly stable.

Also note that the problem is also reported on a CentOS 7.4 kernel a few posts down.

Re: ZFS on Linux: Unlistable and disappearing files

#84

Earlier quoted context omitted.

also a good time to remind people that backups are not backups unless they're geographically diverse. back up to an off site location in case your (home|office) burns down or suffers some other total catastrophe.

> also a good time to remind people that backups are not backups unless they're geographically diverse. ... and backups are not backups until you can reliably restore from them.

...and a DR plan isn't worth the paper it's written on unless you test it regularly (people leave, media gets corrupted... just like the military; do drills!)

Re: ZFS on Linux: Unlistable and disappearing files

#85
post #59

Earlier quoted context omitted.

You've never had problems? You're lucky. I guarantee you will. It took me less than a month to lose significant data with it, under normal usage patterns.

I've been using it for a good 5 years. OK, I had one time. When I removed a disk from a mirror, forced the remaining disk to operate writable as a single, then attempted to migrate it to single disk duplication, then shut it down before it finished migrating. That's not a sane way to handle data really, I was playing around with unimportant stuff. If it was real data, I would have mounted it read only, and copied it…

Well, that is very much the intended use case for a mirror...

Re: ZFS on Linux: Unlistable and disappearing files

#86

Earlier quoted context omitted.

also a good time to remind people that backups are not backups unless they're geographically diverse. back up to an off site location in case your (home|office) burns down or suffers some other total catastrophe.

> also a good time to remind people that backups are not backups unless they're geographically diverse. ... and backups are not backups until you can reliably restore from them.

And that you regularly test that property.

Re: ZFS on Linux: Unlistable and disappearing files

#87

Earlier quoted context omitted.

Debian stable is stretch, released in june 2017. It's on 0.7.5 currently.

correction, I hadn't updated my server in a while, stretch itself is on 0.6.5.9 also, but stretch-backports is on 0.7.6 (not sure when that happened exactly)

> but stretch-backports is on 0.7.6 (not sure when that happened exactly)

[2018-03-09] Accepted zfs-linux 0.7.6-1~bpo9+1 (source amd64 all) into stretch-backports (Aron Xu)

source: https://tracker.debian.org/pkg/zfs-linux

Re: ZFS on Linux: Unlistable and disappearing files

#88

Earlier quoted context omitted.

> also a good time to remind people that backups are not backups unless they're geographically diverse. ... and backups are not backups until you can reliably restore from them.

And that you regularly test that property.

But how do you test that reliably if the filesystem makes files disappear?

I.e., you'll have an original that misses some files, and a backup that misses the same files. A diff will show nothing.

Re: ZFS on Linux: Unlistable and disappearing files

#89

Earlier quoted context omitted.

I believe the most recent issues I've seen documented with it are around the built in RAID5/6 implementation not being fully stable. I haven't used any of it myself so I can't comment on the rest of it. (I did use it on an external drive like 5-6 years ago and had issues that I know have been fixed, but haven't retried it).

They should have kept RAID behind yellow tape for years to come. There's just too many problems that can bite you once a physical disk fails and you really need that RAID to recover.

Yeah, but the distributions are a bit at fault as well. If you use btrfs on SuSE you cannot use RAID5/6 because it is not supported.
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