getting tape speed with iostat or similar

On Tue, Jan 09, 2007 at 01:43:47PM +1100, Duncan Robertson wrote:
> On solaris I can get an idea of the data getting read or written to with
> "iostat" - but in linux iostat does not support tape (st) devices it
> appears, and I haven't found any other way to get this info. Right now
> to see the rate at which something is being written to tape I have to
> try and deduce it (disk read speed, strace, etc), but is there a way to
> get the read/write data rate of st device use?

you could use dd, buffer, bfr or similar programs to buffer the data on
its way to the tape drive. they can all print either a final summary or
progress reports (which either include bps or enough data to calculate
it).

they also tend to speed up tape backups by buffering to the right block
size for optimum streaming on your tape device.

Package: bfr
Status: install ok installed
Priority: extra
Section: utils
Installed-Size: 96
Maintainer: Mark Glines
Architecture: i386
Version: 1.6-0.1
Depends: libc6 (>= 2.3.6-6)
Description: nonblocking 8-bit-clean pipe buffer
bfr's purpose is to buffer data. It buffers from its standard input
and/or a list of files of your choosing, and allows this data to flow
to its standard output at whatever rate that end can handle. It's
useful for any situation in which it's beneficial to have I/O occur in
a detached yet smooth fashion.
Also contained is bfp, a buffering /dev/dsp writer. Pipe your raw PCM
data to it, for skip-free bliss.

Package: buffer
Status: install ok installed
Priority: optional
Section: utils
Installed-Size: 80
Maintainer: Martin Buck
Architecture: i386
Version: 1.19-8
Depends: libc6 (>= 2.3.5-1)
Description: Buffering/reblocking program for tape backups, printing, etc.
Buffer implements double buffering and can be used to keep backup tapes
streaming or printers printing. It can also be used to convert a data
stream to a given output blocksize.
.
Buffer uses shared memory to convert a variable input data rate to a
constant output data rate. It is typically used in a pipe between a backup
program and the tape device, but there are also other applications like
buffering printer data in lpd's input filter.

craig

--
craig sanders (part time cyborg)

--