Messages in this thread |  | | Date | Tue, 2 Oct 2001 13:22:48 -0400 | From | Pete Zaitcev <> |
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> dd if=/dev/hda2 bs=1M|rsh other-system of=/dev/sda2 bs=1M
That does not work on all unixes. Perhaps it does on IRIX, but certainly not on Solaris. The remote dd is going to get short reads from the socket. The telltale sign is the number to short records:
itcev@niphredil /boot]$ dd if=vmlinux-2.4.7-niph bs=8k | ssh pentabug dd of=xxx bs=8k 333+1 records in 333+1 records out 7+653 records in <------- almost all are shorts 7+653 records out [zaitcev@niphredil /boot]$
There is no good way to deal with it, unless you use some external filter (perhaps netcat?). tar has a flag -B to deal with this. An oldtimer's trick is to use compress, which works because zcat uses stdio for output and its blocksize is fixed.
[zaitcev@niphredil /boot]$ dd if=vmlinux-2.4.7-niph bs=8k | compress | ssh pentabug "zcat |dd of=xxx bs=8k" 333+1 records in 333+1 records out 333+1 records in 333+1 records out [zaitcev@niphredil /boot]$
This behaviour of sockets on Linux is entirely normal, so deal with it. My pet peeve is how DaveM insists that WRITES to a socket may return short. That stupidity just makes me furious each time. A socket has a posix-schmozix "right" to return short, I agree. But it is extremely rude and in the right implementation, it should not. It breaks just about _every_ application that uses printk.
-- Pete - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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