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| author | Jim Meyering <meyering@redhat.com> | 2010-06-14 10:15:57 +0200 |
|---|---|---|
| committer | Jim Meyering <meyering@redhat.com> | 2010-06-14 22:36:28 +0200 |
| commit | ceb84598d8c3a166e6949606710771f58eb2be56 (patch) | |
| tree | 333e8c6aa4ab460f0c888702fcb39f2b428b4a86 /doc | |
| parent | 280b15249c9983d61707a00b6a462eb1df448c78 (diff) | |
| download | coreutils-ceb84598d8c3a166e6949606710771f58eb2be56.tar.xz | |
doc: dd: discourage use of very large block sizes
* doc/coreutils.texi (dd invocation): Warn against using a very large
block size. Suggested by Imre Péntek.
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/coreutils.texi | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 26b4eba64..102ceaf97 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -8020,6 +8020,11 @@ followed by a multiplier: @samp{b}=512, @samp{c}=1, @samp{w}=2, @samp{x@var{m}}=@var{m}, or any of the standard block size suffixes like @samp{k}=1024 (@pxref{Block size}). +Any block size you specify via @samp{bs=}, @samp{ibs=}, @samp{obs=}, @samp{cbs=} +should not be too large---values larger than a few megabytes +are generally wasteful or (as in the gigabyte..exabyte case) downright +counterproductive or error-inducing. + Use different @command{dd} invocations to use different block sizes for skipping and I/O@. For example, the following shell commands copy data in 512 KiB blocks between a disk and a tape, but do not save or restore a |