221–230 of 331 posts
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"data security and rot resilience only goes for systems with ECC memory." No. Bad HDDs/SSDs or bad SATA cables/ports cause a lot more data corruption than bad RAM. And ZFS will correct these cases even without ECC memory. It's a myth that the data healing properties of ZFS are useless without ECC memory.
Precisely this. And don’t forget about bugs in virtualization layers/drivers — ZFS can very often save your data in those cases, too.
I just don't get it how the Windows world - by far the largest PC platform per userbase - still doesn't have any answer to ZFS. Microsoft had WinFS and then ReFS but it's on the backburner and while there is active development (Win11 ships some bits time to time) release is nowhere in sight. There are some lone warriors trying the giant task of creating a ZFS compatibility layer with some projects, but they are far f…
Honest question. As an end user that uses Windows and Linux and does not uses ZFS, what I am missing?
Reading any file will tell you with 100% guarantee if it is corrupt or not.
Snapshots that you can `cd` into, so you can compare any prior version of your FS with the live version of your FS.
Block level compression.
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…
More specifically:
> A new device (disk) can be attached to an existing RAIDZ vdev
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My understanding is that single-disk btrfs is good, but raid is decidedly dodgy; https://btrfs.readthedocs.io/en/latest/btrfs-man5.html#raid5... states that: > The RAID56 feature provides striping and parity over several devices, same as the traditional RAID5/6. > There are some implementation and design deficiencies that make it unreliable for some corner cases and *the feature should not be used in production, only…
RAID5/6 is not needed with btrfs. One should use RAID1, which supports striping the same data onto multiple drives in a redundant way.
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RAID5/6 is not needed with btrfs. One should use RAID1, which supports striping the same data onto multiple drives in a redundant way.
How can you achieve 2-disk fault tolerance using btrfs and RAID 1?
RAID1 is just making literal copies, so each additional drive in a RAID1 is a self-sufficient copy. You want two drives of fault tolerance? Use three drives, so if you lose two copies you still have one left.
This is of course hideously inefficient as you scale larger, but that is not the question posed.
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Traditionally, you have the page cache on top of the FS and the buffer cache below the FS, with the two being unified such that double caching is avoided in traditional UNIX filesystems. ZFS goes out of its way to avoid the buffer cache, although Linux does not give it the option to fully opt out of it since the block layer will buffer reads done by userland to disks underneath ZFS. That is why ZFS began to purge the…
what's the best way to deal with this then? disable filecache of linux? I've tried disabling/minimizing arc in the past to avoid the oom reaper, but the arc was stubborn and its RAM usage remained as is
At the time, I had it this way because I had fear of OOM events causing [at least] unexpected weirdness.
A few months ago I discovered weird issues with a fairly big, persistent L2ARC being ignored at boot due to insufficient ARC. So I stopped arbitrarily limiting zfs_arc_max and just let it do its default self-managed thing.
So far, no issues. For me. With my workload.
Are you having issues with this, or is it a theoretical problem?
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>ZFS is mostly for resilient, but not performance critical needs. Los Alamos disagrees ;) https://www.lanl.gov/media/news/0321-computational-storage But yes, in general you are right, Cern for example uses Ceph: https://indico.cern.ch/event/1457076/attachments/2934445/515...
I think what LLNL did predates GPUDirect and other new technologies came after 2022, but that's a good start. CERN's Ceph also for their "General IT" needs. Their clusters are independent from that. Also CERN's most processing is distributed across Europe. We are part of that network. Many, if not all of the HPC centers we talk with uses Lustre as their "immediate" storage. Also, there's Weka now, a closed source sto…
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How can you achieve 2-disk fault tolerance using btrfs and RAID 1?
By using three drives. RAID1 is just making literal copies, so each additional drive in a RAID1 is a self-sufficient copy. You want two drives of fault tolerance? Use three drives, so if you lose two copies you still have one left. This is of course hideously inefficient as you scale larger, but that is not the question posed.
Earlier quoted context omitted.
Traditionally, you have the page cache on top of the FS and the buffer cache below the FS, with the two being unified such that double caching is avoided in traditional UNIX filesystems. ZFS goes out of its way to avoid the buffer cache, although Linux does not give it the option to fully opt out of it since the block layer will buffer reads done by userland to disks underneath ZFS. That is why ZFS began to purge the…
what's the best way to deal with this then? disable filecache of linux? I've tried disabling/minimizing arc in the past to avoid the oom reaper, but the arc was stubborn and its RAM usage remained as is
https://openzfs.github.io/openzfs-docs/Performance%20and%20T...