Re: Oracle on EMC Question

From: Nuno Souto <nsouto_at_optushome.com.au.nospam>
Date: Tue, 19 Mar 2002 12:20:00 GMT
Message-ID: <3c972c04.11183186@news-vip.optusnet.com.au>

Andrew Mobbs doodled thusly:

>I'm not so sure. I keep coming across people with EMC, IBM or Hitachi
>arrays who want to present the storage as a bunch of RAID-5 stripes and
>then position the datafiles accordingly to spread I/O load.
>
>I have no idea why this setup is so popular. IMO it's got all the
>difficulties of a carefully hand-crafted disk layout with the performance
>hit of RAID-5 and none of the ease of SAME.

One reason. You can control the cache allocation/partitioning. And get figures like this:

TABLE_SPACE                    FILE_NAME
READS      BLKS_READ  READ_TIME  WRITES     BLKS_WRT   WRITE_TIME

MEGABYTES
---------- ---------- ---------- ---------- ---------- ----------

---

PSINDEX                        filesystem01
     47037     223772      11391       2353       2353        416
2097
PSINDEX                        filesystem02
     59222     200152      10799       4918       4918        569
2097
PSINDEX                        filesystem03
     67423     246202      12269       3445       3445        501
2097
PSINDEX                        filesystem04
     51513     267111       9842       5330       5330        694
2097
PSINDEX                        filesystem05
     25308      34966      10268       8976       8976       1579

839

Howzat for spread I/O?

Cheers
Nuno Souto
nsouto_at_optushome.com.au.nospam Received on Tue Mar 19 2002 - 06:20:00 CST