I am trying btrfs send/receive a 3TB btrfs volume.

When I sent it to another machine over network, it went fine. The speed was like 20-30 MB/s.

However, when the destination disk is directly attached to the source machine, btrfs send fails after sending like 200-250 GB with send ioctl failed with -5: Input/output error. The speed is above 200 Mb/s.

I checked the source filesystem, did btrfs scrub — all good.

I suspect the I/O error has something to do with trying to read the source too fast. So I would like to throttle it down to 20 Mb/s locally and try.

How can it be done?

1 Answer 1


The error message normally indicates a hardware problem: disk or cables or ...

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