Re: DB File Sequential Read Waits

"rjpfal" <ralbertson_at_comcast.net> wrote in message

>
> Redo logs and their mirrors are on /u07 and /u08 separate volumes.

Are they really separate volumes? Read on.

> Could you clarify on FA here is the disk layout:
> /dev/vx/dsk/ora01dg/u01 8836096 4593114 4110434 53% /u01
> /dev/vx/dsk/ora01dg/u02 53010432 35757224 17118480 68% /u02
> /dev/vx/dsk/ora01dg/u03 70680576 52983600 17558776 76% /u03
> /dev/vx/dsk/ora01dg/u04 26501120 7492696 18859928 29% /u04
> /dev/vx/dsk/ora01dg/u05 11043840 3191368 7791136 30% /u05
> /dev/vx/dsk/ora01dg/u06 11043840 2071456 8902296 19% /u06
> /dev/vx/dsk/ora01dg/u07 33131520 89424 32783960 1% /u07
> /dev/vx/dsk/ora01dg/u08 33131520 3942760 28960768 12% /u08
> NOTE FS Block size is 8K along with oracle block size of 8K

Hmmm, it looks like you got 89M on /u07 in use and a lot more in /u08. How come that's where your logs are? Isn't 89M a bit too small for logs? What else is on /u08 that might interfere with logs?

Still, the problem you have is overall I/O capacity, not just writes? So logs might not be THAT important.

The other thing is: if it's separate volumes on the EMC box for each f/s, then how come the device name above is the same for all f/s? Is this a result of Veritas? I don't recall seeing this when I used EMCs. I wasn't using Veritas.

> Yes no bind variables being used at all. I am talking with developers
> about this now.

Yikes! That alone is a killer... You might need the parameter to take care of parses when bind variables not used, what was it again, anyone?

> > I think You could have also benefited from Locally Managed
> > Tablespaces.
>
> Good point will look into chance of converting.

Definitely. But that alone won't explain the nearly 40ms I/O times. It should be much, much lower than that.

-- 
Cheers
Nuno Souto
wizofoz2k_at_yahoo.com.au.nospam