SMR drives / RAID 5 and 6 levels

Hi Community,

I have a question regarding SMR drives. Is it already possible to use these drives with BTRFS? A other question what is the status of the RAID 5, 6 levels?

@MvL Welcome to the Rockstor community. We have an existing thread that may help on the SMR question:


I think it comes down to if they are host or self managed disks but I don’t know. That thread and the links it contains may help with this question.
And on the btrfs RAID 5, 6 question we also have a rather inactive but still useful thread:

It might be worth waking that thread up if the info you find doesn’t answer you question. I do know that raid 5/6 balances are currently very much under performing time wise in comparison with raid 1 / and 10, ie taking days to complete on large file systems… If in any double I would suggest you go for raid 1 or 10 for the time being.

Hope that helps.

Thank you for your kind words and the links!

I’ve been using a Seagate SMR drive for a week, and all things seem to be going well so far. There was a bug affecting SMR drives that was fixed in kernel version 4.4, so you should probably update your kernel in case you’re using an older install.

BTW, I think all the common SMR drives (Seagate 3.5" 8TB and 2.5" 4TB ones) are drive-managed.

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haoto @haoto , thank you for your reply.

I’ve been using a Seagate SMR drive for a week, and all things seem to be going well so far. There was a bug affecting SMR drives that was fixed in kernel version 4.4, so you should probably update your kernel in case you’re using an older install.

Okay, clear. I have 4 Seagate Archive 8TB (SMR) drives. That is also the one you use?

BTW, I think all the common SMR drives (Seagate 3.5" 8TB and 2.5" 4TB ones) are drive-managed.

You mean self-managed I assume?

Hi @MvL,

Yes, self-managed as in it’s transparent to the host. I’m actually using the Seagate 4TB 2.5" one, but all the information I found was about the one you have.

@haoto thanks for answering!

I’m subscribed to the btrfs mailing list and there was some discussion about RAID 5 / 6. I’m getting the impression RAID 5 / 6 is not production ready yet.