On Mon, May 17, 2021 at 10:29:06AM +0300, Andrei POPESCU wrote: > On Lu, 17 mai 21, 08:32:28, to...@tuxteam.de wrote: > > On Mon, May 17, 2021 at 08:59:43AM +0300, Andrei POPESCU wrote: > > > > [...] > > > > > I'll raise you 'cp': > > > > > > cp foo.iso /dev/sdb > > > > > > > > > which is both fast and short to type (apparently it's smart about using > > > the correct block size). > > > > I'll be sure to try that some day :) > > > > > Unfortunately it's missing dd's equivalent of status=progress. > > > > and oflags=sync. > > Hmm, would you (or anyone else) know what is the difference between > oflags=sync and conv=fsync?
Let me put the docs next to each other (this is from the info page,
which sometimes is more complete than the man page):
* conv=fsync:
‘conv=CONVERSION[,CONVERSION]...’
Convert the file as specified by the CONVERSION argument(s). (No
spaces around any comma(s).)
[...]
The following “conversions” are really file flags and don’t affect
internal processing:
[...]
‘fsync’
Synchronize output data and metadata just before finishing.
This forces a physical write of output data and metadata.
* oflag=sync:
‘oflag=FLAG[,FLAG]...’
Access the output file using the flags specified by the FLAG
argument(s). (No spaces around any comma(s).)
[...]
‘dsync’
Use synchronized I/O for data. For the output file, this
forces a physical write of output data on each write. For the
input file, this flag can matter when reading from a remote
file that has been written to synchronously by some other
process. Metadata (e.g., last-access and last-modified time)
is not necessarily synchronized.
‘sync’
Use synchronized I/O for both data and metadata.
I'd say "conv=fsync" does a sync at the end of the whole thing, while
"oflag=sync" open(2)s the file with O_SYNC (likewise "oflag=dsync"
translates to an open(2) with O_DSYNC), so the sync happens after each
block write. That's what I want, since it gives me much more predictability
as to when I can plop out my usb stick :)
Cheers
- t
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