[install-discuss] Musings on installing B72 x86

[Jürgen Keil]

Bart wrote:

> The more interesting question is
> MB/sec from the dvd drive during the install.

And note that in a lot of cases the MB/sec from the optical drive
during the install is quite low, because hsfs issues 2k read
requests to the drive, even when reading a multi-megabyte
compressed package archive file.  AFAIK, file data on the iso9660
installation media doesn't use sector interleaving, so hsfs could
do a much better job here and read ahead data in bigger clusters.

Test case:  watch "iostat -xnzc 5" while reading from an 
optical media, using different block sizes:

dd if=/dev/rdsk/c2t1d0p0 of=/dev/null bs=2k
dd if=/dev/rdsk/c2t1d0p0 of=/dev/null bs=32k

This SONY DVD RW AW-G170A (and a DVD-RW media)
is reading ~3 MB/sec using 2k read requests, and ~8 MB/sec
when using 32k reads.
 
 
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