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Running mixed raid levels on same disks
- Thread starter maoravni
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To have the more important data more resilient.
I care less if the media is lost than if my photos are lost.
That way if I get the dreaded drive fail while resilvering from a drive fail, the more important data can still be recovered, as it has another spare.
Or am I missing something?
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- Aug 19, 2017
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ZFS will be able to create a pool of partitions. In fact FreeNAS already does this by padding each storage partition with a small swap partition.
What you want to do could be done in FreeBSD, but FreeNAS will not let you do it. Even if you build your own pools using cli, it will be impractical to maintain.
What you want to do could be done in FreeBSD, but FreeNAS will not let you do it. Even if you build your own pools using cli, it will be impractical to maintain.
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I too wish I could have had my media on RAID-Z1, (it's backed up twice), and everything else on RAID-Z2.
Part of the issue is size. With the way ZFS works at present, you can't really manage this with 2 pools on a single group of disks via partitioning. If you mis-calculate the size of one side or the other, then it's full rebuild time. Even using
Part of the issue is size. With the way ZFS works at present, you can't really manage this with 2 pools on a single group of disks via partitioning. If you mis-calculate the size of one side or the other, then it's full rebuild time. Even using
copies=2 on a RAID-Z1 won't help if you loose 2 disks.
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Doable yes, highly unsupported by FreeNAS.
What you're describing is akin to the "virutal RAID" or "distributed RAID" levels used by a few different SAN vendors, done by "slicing up" a disk into many smaller partitions, and then building arrays from those with the desired redundancy.
You'll run into some serious mechanical issues doing this on spinning disks as they'll be seeking all over the place, so without a fast, spacious, and very lazily-flushing write cache in front of it all, performance will be pretty poor.
Could I do it? Absolutely. Will I, now that you've piqued my curiousity? Probably, I've got a few spare machines I can do this with. But would I do it in production? No. I'd just buy more disks. ;)
What you're describing is akin to the "virutal RAID" or "distributed RAID" levels used by a few different SAN vendors, done by "slicing up" a disk into many smaller partitions, and then building arrays from those with the desired redundancy.
You'll run into some serious mechanical issues doing this on spinning disks as they'll be seeking all over the place, so without a fast, spacious, and very lazily-flushing write cache in front of it all, performance will be pretty poor.
Could I do it? Absolutely. Will I, now that you've piqued my curiousity? Probably, I've got a few spare machines I can do this with. But would I do it in production? No. I'd just buy more disks. ;)
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