Re: 600 Gb migration from Sun to Aix in 8 hrs

Mark,

One can obtain an IO size of 1024 kilobytes even on win32 for file operations such as a full table scan or a fast full index scan. Agreed that the values he posted fail a sanity check and will likely be ignored or sanitized.

Whether or not one obatins anything close to that is a matter of testing it out in your environment. In practice, even for a carefully constructed test case, the average read size was less than 50% of the theoretical limit (8192 db_block size, dbfmbrc = 128). Reads such as block headers, smaller extents, block in the buffer cache cause the reads to be smaller than the dbfmbrc.

Grab a copy of filemon.exe from sysinternals to log the filesystem calls.
It allows you to filter on what files of interest you wish to log access to.

Jonathan Lewis covers this in detail in his latest book and elsewhere.

SQL> show parameter db_file_multiblock_read_count

NAME                                 TYPE        VALUE


------------------------------------ ----------- -----

db_file_multiblock_read_count        integer     32

  1 select pname, pval1
  2 from sys.aux_stats$
  3 where pval1 is not null
  4* order by 1
SQL> /

PNAME                               PVAL1


------------------------------ ----------

CPUSPEED                              587
CPUSPEEDNW                     1051.42512
FLAGS                                   1
IOSEEKTIM                              10
IOTFRSPEED                           4096
MAXTHR                            3555328
MBRC                                    7
MREADTIM                           10.513
SREADTIM                            4.536

9 rows selected.

10.1.0.4 std ed. 32 bit
w2k adv svr sp4
HP DL530G2
dual xeon mp 2.4 GHz
datafiles exclusively on an 8 drive RAID 10 volume, stripe size 256 KB

-bdbafh
Received on Mon Nov 21 2005 - 18:00:25 CST