Read in a page or a filesystem block?

[Yong Huang]

According to Richard McDougall
(sunsite.uakom.sk/sunworldonline/swol-06-1999/swol-06-filesystem2.html),
on Solaris, system call tracing

read(3, "\0\0\0\0\0\0\0\0\0\0\0\0".., 512) = 512
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0".., 512) = 512
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0".., 512) = 512
...

means that only 1 physical read of 8k data is read by the first read()
and subsequent read()'s are read from memory. My question is, is the
8k the memory page size (`pagesize`) or the file system block size
(`df -g | grep "block size"`)? On sun4u architecture both are 8k. But
on sun4m for instance, pagesize is 4k and file system block size could
be either 4k or 8k. Is there any way to find out, by iostat, sar or
writing a small C program?

Yong Huang
yon...@yahoo.com